The ASA property Animation Play

The congruent trapezium Simulation Play

The congruent triangle Simulation Play

The counterexample Whiteboard exercise Play

The pairs of congruent figures Simulation Play

The perpendicular bisector in a circle Animation Play

The perpendicular bisector of a line segment Animation Play

The perpendicular bisector of a line segment – a reminder Student activity Play

The SAS property Animation Play

The Side-Angle-Side (SAS) property Whiteboard exercise Play

The Side-Angle-Side property Whiteboard exercise Play

The Side-Side-Side (SSS) property Whiteboard exercise Play

The Side–Angle–Side (SAS) property – observations and generalisation Student activity Play

The Side–Side–Side (SSS) property Student activity Play

The SSS property Animation Play

Triangles Whiteboard exercise Play

When is a theorem false? The counterexample Student activity Play

Yoko cleans her room Animation Play