GeometryForge

Geometry is something you build. Make angles, raise polygons, slide and flip shapes across a grid, and stretch a band to an exact area — then meet the guides who each embody one geometric idea.

Level 1

For grown-ups — progress report →A private, on-device snapshot mapped to the skill areas practiced. Export a CSV or print — nothing leaves this device.

Build & reason — hands-on geometry surfaces

Six ways to do geometry, rebuilt for the browser — the same skills as the iOS app, plus two you can only do here.

Property-Chain Reasoning ✨ new Build a proof yourself: pick the deduction that follows next — vertical angles, triangle sums, parallel lines, exterior angles — until you reach the conclusion. Every wrong pick explains why. Fill the Point ✨ new Discover which shapes tile: place polygon corners into a vertex and watch them fill toward exactly 360° — no gap, no overlap. Six triangles? Three hexagons? A square and two octagons? Geometry Studio Make an angle to a target with a live protractor, build a polygon to a given interior-angle sum, and set complementary & supplementary pairs. Transformation Lab Slide, flip, turn, and scale shapes on a coordinate grid: name the transformation, tap where a vertex lands, and find a shape’s line of symmetry. Geoboard Stretch a rubber band around the pegs to enclose an exact area — and watch Pick’s Theorem balance as you drag. Concept practice 17 short question rounds, from points & angles up to advanced synthesis — pick one below.

Practice the concepts

17 kits from an intro to points & angles up to advanced synthesis — a short round of questions with a hint whenever you get stuck. Your progress stays on this device.

Kit 1: Points, Lines, and Angles Angles & lines · grades 4-5 · 25 questions Kit 2: Classifying 2D Shapes Shapes · grades 4-5 · 25 questions Kit 3: Area and Perimeter Measurement · grades 5-6 · 25 questions Kit 4: 3D Shapes and Volume Measurement · grades 5-6 · 25 questions Kit 5: Symmetry and Transformations Transformations · grades 5-6 · 25 questions Kit 6: Coordinate Geometry Coordinate geometry · grades 6-7 · 25 questions Kit 7: Pythagorean Theorem Measurement · grades 7-8 · 25 questions Kit 8: Geometric Proofs and Reasoning Reasoning & proof · grades 7-8 · 25 questions Kit 9: Circles & Arc Measures Circles · grades 6-8 · 25 questions Kit 10: Similarity & Scale Similarity & congruence · grades 6-8 · 25 questions Kit 11: Intro to Trigonometry Measurement · grades 7-8 · 25 questions Kit 12: Geometric Constructions Constructions · grades 6-8 · 25 questions Kit 13: Cross-Topic Connections Reasoning & proof · grades 5-6 · 25 questions Kit 14: Real-World Applications Reasoning & proof · grades 6-7 · 25 questions Kit 15: Misconceptions & Reasoning Reasoning & proof · grades 6-7 · 25 questions Kit 16: Advanced Synthesis Reasoning & proof · grades 7-8 · 25 questions Kit 17: Congruence and Triangles Similarity & congruence · grades 6-8 · 10 questions

Play together · new on the web

Geometry Duel — a head-to-head kit round for 2–4 players. Take turns on one device, or join a friend in an online room by code. Highest first-try score wins; no chat, no accounts.

⚔️ Start a Geometry Duel →

🔀 Mixed practice — revisit what you’ve learned A short round that shuffles questions from the kits you’ve played, brought back when they’re ready to review. Great for making it stick.

Same idea, another world

Something you practice here shows up somewhere else too — that's real learning that travels.

Enlarging a shape by a scale factor multiplies every side by the same number — that fixed multiplier is a ratio.The shared idea: a fixed scale factor (y = kx) — a dilation multiplies every length by the SAME number, exactly the fixed ratio you scale a proportion byTry RatioRealm →Flipping a shape across its mirror line is exactly how light reflects off a mirror — the angle in equals the angle out.The shared idea: reflection — flipping a shape across its line of symmetry is the same mirror reflection as a light ray bouncing so the angle in equals the angle outTry PrismForge →
GeometryForge mascot

Meet the cast — the characters who teach this

Each one stands for an idea you’ll practice. Tap a character to read their illustrated story and hear their audio drama.

Ensemble stories — the cast together

Explore all the stories →

📚 Books for GeometryForge

Read the story, print a workbook, or color the cast — free PDFs to read offline or print at home.

Browse all books →

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