How do I teach geometry online? (Or: what to reach for when a hand-drawn triangle on a screenshare isn't cutting it)

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Teaching geometry online works when three things sit on the shared canvas together: shapes the student can drag, resize, and rotate, with side lengths and angle measures you label onto them (so a triangle isn't a picture but an object the student is placing next to a square); the geometry notation you'd write on paper (° for angles, ∠ for angle marks, △ for triangle references, ⊥ and ∥ for perpendicular and parallel, √ for square roots); and — for the parts a static shape can't teach — a paired dynamic-geometry tool like GeoGebra opened inside the lesson via a cobrowser, for the constructions, transformations, and drag-a-vertex-and-watch-everything-update mechanics that made in-person geometry lessons tick. On Koala Go, the shapes live in the Whiteboard Library's Math Tools panel with a two-tier split — the elementary and general-purpose shapes on Pro, the fuller polygon-and-solid library plus shape labels on Platinum — and the geometry symbols sit in the same Math Symbols palette that covers the rest of the notation side of math tutoring. The rest of this page walks through which shapes teach which concepts, how the labels and notation sit against them, when to pair GeoGebra, and where the tier lines actually land.

Why teaching geometry online is a specific kind of hard

Geometry is the subject in the elementary-and-secondary math curriculum that most obviously wants a physical object in the child's hand. In an in-person lesson you'd reach for a set of pattern blocks to sort by number of sides, a protractor to measure the angle between two lines, a paper triangle to fold along its line of symmetry, a set of plastic solids to count faces on, a compass and straightedge to bisect an angle. Almost none of that survives a webcam and a screenshare. The three problems below are what every online geometry tutor names in some form.

The shapes-as-objects problem. A drawn shape on a slide is a picture; a geometric object is a thing the student can move and compare. "Is this rectangle a square?" is answered differently when the student can drag the corner and watch the sides change than when they're looking at a static image. "How does the hexagon compare to two trapeziums?" is a question that only lands when both are on the same canvas and the student can slide the trapeziums into the hexagon's outline. Screensharing a slide gives you the picture; it doesn't give you the composition. And pen-drawing a rough shape on the whiteboard gets you neither: it's neither the picture nor the manipulable object, and the sides are lumpy.
The notation problem. Real geometry writes in symbols keyboards don't ship — the angle mark (∠ABC), the triangle glyph (△ABC ≅ △DEF), perpendicular (AB ⊥ CD), parallel (AB ∥ CD), degrees (60°), the square-root (√). A student typing "angle ABC = 90 degrees" in a Google Doc is doing the mental work of writing "∠ABC = 90°" without any of the pattern-recognition the notation is meant to trigger. Every symbol they don't have easy access to is a small paper cut that slows the lesson and blurs the notation into English.
The construction and dynamic-geometry problem. Later geometry — from about middle school onwards — is about processes, not just shapes: bisecting an angle with a compass, dropping a perpendicular from a point to a line, constructing a regular hexagon inscribed in a circle, translating a shape by a vector, reflecting a shape across a line, rotating it about a point. In a physical classroom this is a compass-and-straightedge or transparency-and-marker workflow; on paper it doesn't animate; on a static whiteboard it's a snapshot, not a construction. The move that closes this gap online is a paired dynamic-geometry tool (GeoGebra is the standard) opened inside the classroom via the cobrowser — but the whiteboard side still has to carry the definitions, the theorem statements, the notation, and the discussion. Neither surface alone does the whole job.

An online geometry workflow that works has an answer to each: a shape library where each shape is a first-class object the student can grab; a notation palette that puts ∠ ° ⊥ ∥ △ √ one click away; and a cobrowser pairing pattern for the constructions and transformations the static whiteboard can't do. The rest of this page is that answer, on the tools Koala Go ships.

The shape library — 2D and 3D shapes as first-class objects on the whiteboard

The Math Tools panel in Koala Go's Whiteboard Library has two folders on the shape side: 2D Shapes and 3D Shapes. Every shape in either folder is a first-class object on the shared canvas — you or the student can pick one, drop it, drag it, resize it, rotate it, recolour its fill and border, or delete it, and the change syncs to the other side in real time. That's the primitive that makes online geometry teachable: the shape isn't a picture you're describing, it's an object the student is composing with.

2D shapes: what you get on which tier

The 2D folder ships with 21 shapes across two tiers. The Pro tier ($25.99/month monthly, $21.99/month annual) covers the elementary and general-purpose set — square, rectangle, circle, equilateral triangle, plus straight line, dashed line, and arrow as 1D line primitives that live in the same folder. That's 7 shapes, and it's enough for most K-5 geometry: shape recognition, symmetry, area and perimeter of rectangles and circles, basic angle work with equilateral triangles, and any lesson that needs a straight-line diagram.

Platinum ($49.99/month monthly, $39.99/month annual) adds the fuller polygon library plus non-equilateral triangles and curved 2D shapes. The additional 14 shapes:

Regular polygons and other quadrilaterals: rhombus, parallelogram, trapezium, kite, pentagon, hexagon, octagon.
Non-equilateral triangles: isosceles triangle, scalene triangle, right-angle triangle. Middle-school geometry leans on these — the specific "here's a right-angle triangle, work out the missing side with Pythagoras" moment doesn't work if the only triangle in the folder is equilateral.
Curved 2D shapes: oval, semicircle, sector, segment. The sector shape is the one to know if you teach the sector-area formula A = (θ/360) × πr² — it renders as a pie-slice you can label the angle and radius on, and it pairs cleanly with the Fraction Circles from the fractions spoke for the "a sector is a fraction of a circle" moment.

Every shape has a rigidity — either fixed (uniform scaling on corner drag, so a square stays a square and a circle stays a circle) or flexible (independent width/height scaling, so a rectangle can become tall and narrow and an oval can stretch into an ellipse). Fixed rigidity is what you want when the shape's identity depends on its proportions (the square, the equilateral triangle, the regular polygons, the circle). Flexible rigidity is what you want when the shape is a rectangle-family object whose whole point is that the width and height are independent (the rectangle, the parallelogram, the trapezium, the oval, all three non-equilateral triangles — isosceles, scalene, and right-angle — and the lines).

3D shapes: what you get on which tier

The 3D folder ships with 10 solids across two tiers. The Pro tier includes exactly one 3D shape — the cube. That's it. Every other 3D solid is on Platinum. This is a real product boundary to know about: a Pro tutor who teaches faces, edges, and vertices of solids has one solid in the folder, and everything else needs Platinum.

Platinum adds 9 more 3D solids, covering the standard middle-school and secondary-geometry set:

Prismatic solids: cuboid, triangular prism.
Round solids: cylinder, sphere, hemisphere, cone, torus.
Pyramidal solids: square pyramid, tetrahedron.

Two honest things to know about the 3D solids specifically. First, they're rendered as shaded 2D projections of a solid — you can drag, resize, and rotate them in the canvas plane, but you can't spin the solid in space to see a different face. For teaching a student to count faces, edges, and vertices, to compute surface area and volume from given dimensions, or to identify a solid from its properties, the projection is fine — you point at a face and the student counts. For teaching a student to visualise the same solid from a different angle, a paired GeoGebra 3D tab (see below) does more than the projection can. Second, the labelled edges and vertices on a 3D projection are always the ones the projection shows — the "back" edges and vertices of a cube, for instance, are drawn but aren't as directly clickable as the front ones, so if you're teaching a "how many edges does a cube have?" lesson, the labels do more of the work than the object itself. This is normal for any 2D-rendered solid; it's the trade-off of the projection format.

Shape labels: side lengths, angle measures, and vertices attached to the shape

The single feature that most changes what geometry teaching feels like on a shared whiteboard is shape labels. When labels are enabled (via the Show shape labels toggle in the Math Tools panel — Platinum), every placed shape shows a small "+" placeholder at each of its anchor points: corners for polygons, edges for circles and ovals, tips and base corners for pyramids and cones and sectors. Click any "+" and it drops an editable text box anchored to that shape point. Type "6 cm", "60°", "A", or whatever the lesson needs, and the text stays attached — when you drag the shape, the label moves with it; when you resize the shape, the label repositions to keep its relative place near the anchor.

What this means for a working geometry lesson:

Vertices labelled with capital letters. Drop an equilateral triangle, click the top corner and label it "A", click the bottom-left corner "B", click the bottom-right "C". Now you can write ∠BAC on the whiteboard, refer to "△ABC" in the notation, and the student sees where each vertex is on the picture. This is the base workflow for any theorem-based lesson from middle school onwards.
Side lengths on rectangles, triangles, and polygons. Drop a right-angle triangle. Anchor labels to the two legs — "3 cm" and "4 cm" — and to the hypotenuse — "5 cm" (or leave the hypotenuse blank as the value to work out). Now you have a labelled Pythagoras problem the student is looking at while writing the answer in a text box next to the picture. Anchor labels rescale correctly when you resize the triangle, so if you scale it up to make it easier to see, the labels stay where they should.
Angle measures. Drop a scalene triangle (Platinum). Label each vertex with its angle measure — "60°", "80°", "40°" — and the labels move as you drag the shape. Now the "sum of interior angles of a triangle" question is a visible fact.
Radius and diameter on circles. Drop a circle, anchor a label to the edge with "radius = 5 cm", and the label stays where it should when the circle is repositioned.

Two things worth knowing plainly about how labels work. First, labels are text, not live-computed values — you type the measurement, and the text doesn't update automatically if you resize the shape. So a "6 cm" label on a rectangle that you then stretch to twice its width still reads "6 cm" until you edit the text. This is normal for a labelling system on a static whiteboard; live measurement of a drawn or dragged shape belongs on GeoGebra, in the cobrowser pairing pattern below. Second, enterprise and B2B tutors are provisioned at the Pro feature level and Platinum-only controls are hidden entirely from their UI — meaning an enterprise tutor doesn't see the labels toggle at all, and the labelling workflow above isn't available to them without a plan upgrade the enterprise administrator would have to arrange. On Free and standard Pro, the labels toggle is visible but locked behind a Platinum upgrade prompt.

Pro-tier workaround when you don't have labels: place regular text boxes next to the shape by hand. Fine for a lesson with one or two labelled shapes; painful for a lesson with a dozen labelled polygons and re-arrangement — every text box has to be re-positioned when you move the shape, because the boxes aren't anchored. If your caseload is geometry-heavy and you're on Pro, the labels toggle is the single strongest reason to look at Platinum.

Geometry notation on the whiteboard — degrees, angles, radicals, perpendicular, parallel

The Math Symbols palette on Koala Go's whiteboard has a Geometry category with the symbols you'd reach for in a geometry lesson. On Koala Pro you get ° (degrees) and √ (square root) — the two most-used geometry symbols in elementary and middle-school work. On Koala Platinum you additionally get ∠ (the angle marker used in ∠ABC), △ (the triangle glyph used in △ABC ≅ △DEF), ⊥ (perpendicular, as in AB ⊥ CD), and ∥ (parallel, as in AB ∥ CD).

The palette lives in two places on the same whiteboard: a Math Symbols folder in the Whiteboard Library (discovery surface) and a ∑ button that appears next to any selected text box or sticky note (speed surface, inserts at the cursor). Both entry points and the six common notation moves are walked through in the write math equations online spoke; here we just call out the geometry-specific patterns:

Angle measures on a labelled shape. Anchor a label to a vertex and type the measure straight in — "60°" (the degree sign is Option+Shift+8 on a Mac, and long-press the 0 key on an iPad). Worth knowing before you build a lesson around it: the palette's ∑ button appears next to text boxes and sticky notes, not next to shape labels, so palette-built notation belongs in a text box beside the shape rather than inside the label itself. Pair the two — labelled shape, notation in a text box next to it — for the full "here's an angle-sum-of-a-triangle" picture.
An angle name in a theorem statement. Type "The base angles of an isosceles triangle are equal, so ", click ∠, type "ABC = ", click ∠, type "ACB". Now you have a properly-notated theorem statement next to the labelled shape.
A perpendicular or parallel claim. "Since AB ⊥ CD, ∠ADB = 90°." Type "AB", click ⊥, type "CD, ", click ∠, type "ADB = 90", click °. Reads correctly as geometry notation the student will see in an exam.
A congruence or similarity statement. Type "So ", click △, type "ABC ≅ ", click △, type "DEF" — congruent-triangles notation matches the textbook. (The ≅ glyph itself isn't in the palette — if a lesson needs it heavily, the workaround is the ≈ symbol from the Compare category on Platinum, or "==" spoken as "is congruent to". Same known-limit as the notation spoke's honest "not a full equation editor" section.)
Answers with a radical. Type "The diagonal of a unit square is ", click √, type "2." — Pythagoras answers where the value doesn't simplify to a rational stay in radical form.

For the full palette walkthrough, the entry-point mechanics, and the honest limit on stacked fractions and rendered LaTeX layouts (which do bite on late-secondary geometry work — no radicand-under-a-bar on √, superscripts stop at ⁿ, no matrix layouts), see the notation spoke.

Constructions and dynamic geometry — pair a cobrowser tab into GeoGebra

The shape library above is a great labelling and discussion surface — students can compose with shapes, annotate them with notation, and reason about their properties. What it is not is a construction environment. If a lesson needs compass-and-straightedge constructions, transformations that update dependent measurements live, or a locus of points that traces as the student drags a vertex, the honest answer is: pair a cobrowser tab into GeoGebra alongside the whiteboard.

A cobrowser is a shared browser window inside the classroom — you open a page and both you and the student can click, type, and interact with the page live, not screen-sharing but actual shared control. GeoGebra (the standard free dynamic-geometry tool) opens cleanly in the cobrowser; both of you can use the compass tool to bisect an angle, drag a vertex to see how a shape's other measurements respond, translate/rotate/reflect a shape and watch the image position update, or trace a locus of points on a moving construction. The mechanic is covered in depth in the what is a cobrowser? explainer.

The pairing pattern most working online geometry tutors converge on is:

Whiteboard side (Koala Go's Math Tools). Definitions, theorem statements with the ∠ △ ⊥ ∥ ° notation, labelled shapes as pictures to reason about, PDF past-paper problems annotated with palette symbols, static diagrams for a proof.
Cobrowser side (GeoGebra or a similar dynamic-geometry tool). Actual constructions (bisect this angle, construct the incentre, inscribe a regular hexagon), transformations (translate △ABC by the vector, rotate about the origin), dynamic drag-a-vertex investigations, coordinate-geometry work where the point moves and the equations update.

On Koala Free, the cobrowser is capped at 10 minutes per session with a 20-minute cool-down. That's enough for a short GeoGebra demo but too tight for a full lesson driven from GeoGebra. On Koala Pro (and up) the cobrowser is unlimited. So for a geometry-heavy caseload the Pro-and-up floor for cobrowser is functionally the same practical floor as it is for exam-prep and general tutoring workflows.

Other tools in the same pairing pattern that some tutors prefer: Desmos Geometry for its simpler interface (better suited to middle-school constructions than GeoGebra's full toolbar), Mathigon Polypad for the virtual-manipulatives style of geometry work, and subject-specific applets from PhET Interactive Simulations for physics-adjacent geometry (light rays, projectile paths). Each opens in the cobrowser the same way.

A working sequence for teaching geometry online, by age band

Different age bands lean into different parts of the toolkit. Grade bands are typical US placements, not standards claims — adapt to the student and curriculum in front of you.

K-2 (ages 5-7): shape recognition and simple properties. Use the Pro 2D set — square, rectangle, circle, equilateral triangle — plus the Pro cube. Sorting activities ("place the shapes that have four sides on the left"), matching ("point at the shape that has three corners"), simple symmetry ("draw a line down the middle of the square that makes two matching halves"), first vocabulary (sides, corners, vertices). Notation is minimal at this age. Playground / Gems / avatars carry the engagement layer between short activities — see the gamified virtual classroom explainer. Every Koala Pro tutor has what they need for K-2 geometry without touching Platinum.
Grades 3-5 (ages 8-10): area, perimeter, and the introduction of angles. Area and perimeter of rectangles and squares (Pro shapes cover it) with side-length labels typed in text boxes next to the shape (Pro workaround) or attached as anchor labels (Platinum). Introduction to angle types — acute, right, obtuse — with the ° symbol from the palette. Introduction of 3D solids in the curriculum happens here in many US programs, and this is the tier line where Platinum starts to earn its keep: Pro has the cube; Platinum has cuboid, triangular prism, cylinder, sphere, hemisphere, cone, square pyramid, tetrahedron, torus — the standard elementary-and-middle-school 3D solids set. A Pro tutor teaching "count the faces on a triangular prism" has to draw one; a Platinum tutor drops one from the folder.
Middle school (ages 11-13): the full polygon set, angle theorems, volume, surface area, and the introduction of formal notation. The Platinum polygon library (rhombus, parallelogram, trapezium, kite, pentagon, hexagon, octagon; isosceles / scalene / right-angle triangles) opens up angle-sum theorems, interior/exterior angles, the naming of polygons by their number of sides. The full 3D-solid Platinum library carries the volume and surface-area formulas — cylinder, cone, sphere, square pyramid, triangular prism — with dimensions labelled on the picture (Platinum shape labels). The ∠ △ ⊥ ∥ symbols from the palette (Platinum) come in with the introduction of formal notation. Shape labels (Platinum) become almost required here — a lesson on angle-sum-of-a-quadrilateral is a lot less useful without the four vertex angles labelled on the shape. This is the tier at which most geometry-focused tutors move to Platinum.
Secondary (ages 14-17) and adult learners: coordinate geometry, transformations, constructions, and proofs — whiteboard for notation, GeoGebra in the cobrowser for the dynamic work. Coordinate geometry uses the -10 to 10 number line from the number-sense spoke as a ready-made x-axis, with pen and shape tools to draw the y-axis; the shape library lets you drop lettered points and lines. But most of the dynamic work at this level (bisecting an angle, dropping a perpendicular, reflecting a triangle across a line, constructing an incentre) belongs on the paired GeoGebra tab — the whiteboard is where the theorem, the notation, and the proof-writing live. Uploaded past-paper PDFs (Pro) become the primary surface for exam-focused geometry — see how to teach exam prep online for the SAT / ACT / A-level / IB exam-focused version of this workflow.

Practice, homework, and past-paper geometry problems

The shape library and notation palette carry the teaching; consolidation runs on practice. Two patterns most working online geometry tutors converge on:

Upload the student's homework worksheet as a PDF and annotate on top of it. On Koala Pro, PDF and PowerPoint upload sits alongside the shape library — the worksheet becomes the lesson surface, both you and the student annotate on the same page with pens, shapes, and text boxes. For a geometry worksheet with printed shapes and blank angle-measure lines, this collapses the "here's your homework, let's go through it" workflow from a screenshare-and-narrate into a real shared workspace. Shape labels attach to shapes you drop on top of the PDF the same way they do on a blank canvas.
Cobrowser to interactive geometry practice sites. Bring the student into the practice, don't send them out to it. Khan Academy has strong geometry practice sets across grade bands; IXL has structured skill practice; GeoGebra has a large community-authored applet library for specific concepts; Brilliant.org has courses in Euclidean geometry. Open the site in the cobrowser and both of you interact with the page live — you see exactly what the student typed, what shape they dragged where, and can jump in without them window-switching.

Between-lesson practice for geometry-heavy students works best as a very small, specific ask — "draw three quadrilaterals in your notebook with your parent, one that has all four sides equal, one that has exactly one pair of parallel sides, one that has none" — rather than "practise geometry for 30 minutes." The homework workflow that most tutors converge on is covered in how do I give homework to online tutoring students?

Common failure modes and honest limits

Things that go wrong in online-geometry workflows, and the fix:

Trying to draw shapes with the pen tool rather than the shape library. A hand-drawn rectangle on a whiteboard is a picture; a Rectangle from the shape library is an object with corner anchors for labels, uniform resize handles, and a real fill and border. The pen is for freehand annotation (an arrow, a construction line, a scribbled note); the shape library is for shapes the lesson is about. Every geometry lesson should start with the shape from the folder and annotate on top with the pen, not the other way round.
Placing text boxes near shapes on Pro and expecting the labels to move with the shape. Text boxes on Koala's whiteboard are independent objects — they don't follow the shape when you drag it, so a labelled shape you re-arrange has to be re-labelled by hand. Anchored shape labels (Platinum) are the fix: labels attached to the shape's corner/edge/tip anchors move and resize with the shape. If you're on Pro and doing more than a couple of labelled shapes per lesson, this is the friction point that pushes most tutors to Platinum.
Expecting the 3D solids to rotate in space to show a different face. Koala Go's 3D solids are rendered as shaded 2D projections — you can drag, resize, and rotate them in the canvas plane, but you can't spin the cube to see the back face. This is fine for counting faces / edges / vertices, computing surface area and volume from labelled dimensions, or identifying a solid from its properties. It is not a substitute for a 3D-manipulable model when a student needs to visualise how a solid looks from a different viewpoint. Pair a GeoGebra 3D tab in the cobrowser for that specific case, or a physical set of solids the student has at home.
Expecting shape labels to auto-measure the shape. Labels are text boxes anchored to shape anchors; the tutor types the value ("6 cm", "60°", "A"). If you resize the shape, the label repositions correctly but the text doesn't update — a "6 cm" label on a rectangle you then stretch still reads "6 cm" until you edit it. This is normal for a labelling system on a static whiteboard; live measurement of a drawn or dragged shape belongs on GeoGebra.
Trying to construct a shape from scratch on the whiteboard. Bisecting an angle, dropping a perpendicular, inscribing a circle in a triangle, constructing a regular hexagon by compass-and-straightedge — none of these are possible from the whiteboard's tools, and no combination of pen + shape + line will approximate the mechanic. This is the honest "pair GeoGebra in the cobrowser" limit — for any lesson whose whole point is the construction, the shared shape library is the wrong surface. Whiteboard for the definition and the theorem; cobrowser tab for the compass.
Free-tier tutors seeing every shape locked. The 2D and 3D folders in the Whiteboard Library show a locked banner on Free — the shape library is a Pro-and-up feature. A tutor trialling Koala Go for geometry needs at least the trial or Pro plan to evaluate.
iPad-only workflows. Koala Go works on iPad, but the precision needed to grab a corner anchor on a small shape, drop a label into the "+" placeholder, and drag exactly the right vertex is fiddlier on a finger than on a mouse. If your student uses an iPad exclusively, plan around larger placed shapes (resize the shape up to make anchors easier to hit), and prepare more of the labelling in advance on your side so the student's job on iPad is dragging and arranging shapes rather than fine-anchor picking.

Three limits worth naming plainly rather than papering over:

Every 3D solid except the cube is Platinum. A tutor teaching 3D geometry regularly wants Platinum, plain and simple — Pro's single 3D solid (the cube) covers the "count the faces on a cube" lesson and nothing else. Factor this into the plan choice; a middle-school geometry caseload on Pro is going to be leaning heavily on hand-drawn 3D solids or paired GeoGebra tabs for anything past the cube.
Shape labels are Platinum-only, and hidden entirely from B2B / enterprise UI. A Platinum-tier tutor gets the anchor-labels workflow described above; a Pro-tier tutor uses the manual text-box workaround; an enterprise tutor doesn't see the labels toggle at all (provisioned Pro-level, Platinum controls hidden). For a geometry-heavy B2B deployment, this is a real friction point worth naming to the administrator before the account is set up.
No compass-and-straightedge constructions, no auto-measurement, no dynamic-geometry drag-a-vertex mechanic on the whiteboard. The shape library is a labelling and discussion surface, not a construction environment. Constructions, transformations that update measurements live, and dynamic geometry pair with GeoGebra in the cobrowser — described above. This is a real product line, not a shipping-soon promise: dynamic geometry lives on the paired tool.

Practical setup on Koala Go for a geometry-heavy caseload

If you're evaluating Koala Go for K-secondary geometry specifically, here's the practical picture and where the current lines sit:

Whiteboard is the workspace. The classroom's whiteboard is a Fabric.js canvas with the Math Tools panel: 7 Pro 2D shapes + 1 Pro 3D shape + 14 Platinum 2D shapes + 9 Platinum 3D shapes + the Math Symbols palette for geometry notation. Both tutor and student can place, drag, resize, rotate, recolour, and delete shapes; the state syncs live and persists across lessons.
Upload existing geometry worksheets and past papers. On Pro, upload the student's textbook page, homework worksheet, or past-paper geometry problem as a PDF or PowerPoint. Annotate on top with pen, shape, and text tools; shape labels (Platinum) attach the same as they do on a blank canvas.
Cobrowser for GeoGebra, Desmos Geometry, Mathigon Polypad, Khan Academy, IXL. Open the site in the classroom's cobrowser and both of you click and drag on the live page. 10 minutes at a time on Free with a 20-minute cool-down; unlimited on Pro. See what is a cobrowser? for the mechanic.
Playground and Gems for the K-2 engagement layer. The youngest grades (pre-K through grade 2) benefit most from the Playground brain break between shape-sorting activities and per-student Gems for immediate effort-based reinforcement. Older students lean into the shapes and notation without needing the engagement layer as heavily. See gamified virtual classroom for the depth.
Recording for parent review or student self-review. Local recording is on Pro; cloud recording of scheduled lessons comes with Platinum. Both support the "send the parent a clip of today's angle-sum-of-a-triangle breakthrough" pattern. See record online tutoring lessons for the consent, storage, and sharing pattern.
Free tier limits worth knowing. Koala Free caps sessions at four students, includes the whiteboard plus image upload plus a capped cobrowser, but the Math Tools panel (shapes, number lines, math symbols, rods, fractions) is all Pro-and-up. Free is a trial surface for geometry, not the day-to-day.

Honest limits worth flagging that show up in real geometry work regardless of platform: iPad is rougher than desktop for narrow-anchor picking; students in mainland China sometimes hit connection issues (we route through Hong Kong proxies but the Great Firewall is a moving target — see teaching students in mainland China for the workaround pattern); and every 3D solid past the cube plus shape labels plus the ∠ △ ⊥ ∥ notation is Platinum, so middle-school and secondary geometry-heavy caseloads pretty much live on Platinum by design.

Where Koala Go isn't the right pick for geometry

Two honest tradeoffs worth naming, so you know before you sign up:

Dedicated dynamic-geometry as the primary surface. If every lesson you teach is a compass-and-straightedge construction or a drag-a-vertex-and-watch-the-measurements-update investigation, GeoGebra as the primary teaching surface (with a separate video-call tool for the face and voice) can be a cleaner fit than pairing Koala Go's whiteboard with a GeoGebra cobrowser tab. Koala Go's shape library is a labelling and discussion surface with a cobrowser pairing for the dynamic work — a strong fit for a mixed caseload (definitions, notation, past papers, discussion, occasional constructions), less obviously the strongest fit for a pure-dynamic-geometry practice.
Whole-class delivery to a 25-student geometry class. Koala Go is calibrated for 1-on-1 and small-group tutoring — the Free tier caps sessions at four students. It's not designed for a full school-class synchronous geometry lesson of the kind Nearpod or Pear Deck are built for. For a whole-class shape, look at platforms built for whole-class delivery.

How do I teach geometry online? (Or: what to reach for when a hand-drawn triangle on a screenshare isn't cutting it)

Why teaching geometry online is a specific kind of hard

The shape library — 2D and 3D shapes as first-class objects on the whiteboard

2D shapes: what you get on which tier

3D shapes: what you get on which tier

Shape labels: side lengths, angle measures, and vertices attached to the shape

Geometry notation on the whiteboard — degrees, angles, radicals, perpendicular, parallel

Constructions and dynamic geometry — pair a cobrowser tab into GeoGebra

A working sequence for teaching geometry online, by age band

Practice, homework, and past-paper geometry problems

Common failure modes and honest limits

Practical setup on Koala Go for a geometry-heavy caseload

Where Koala Go isn't the right pick for geometry

Related answers in the math cluster

More answers on this topic