Math · Foundational

Geometry: Visual Proofs

Drag triangles, slide shapes apart and rearrange slices of a circle. You'll see why the classic geometry facts are true, not just memorise them.

9 lessons~55 min0/9 complete

Angles

Straight lines, parallel lines and triangles.

Cut, slide and rearrange.

π, and what happens when shapes grow.

Transformations, congruence and coordinates.

Ready for more? These courses use what you learn in Geometry: Visual Proofs.

Inscribed angles, Thales, cyclic quadrilaterals, tangents, sectors and the power of a point.

Build geometry from two simple tools, and discover the problems they can never solve.

Fold paper to the Moon, find the rules of flat folding, and trisect angles that a compass can’t.

How artists draw depth, why parallel rails meet, and the number that survives every projection.

Triangles, the unit circle, waves, surveying and navigation: the mathematics of angles.

Platonic solids, Euler’s formula, volumes, cross-sections and nets.

Which shapes tile the plane, Escher’s tricks, friezes, and patterns that never repeat.