Maths

A shape is congruent if it has same size and angles as another shape.
If shapes are congruent they are identical.

Proof 1 (Side Side Side) SSS:
All 3 sides of the triangle are the same length meaning the triangles must be congruent.
Proof 2 (Side Angle Side) SAS:
Two sides are the same length so the angle in between them is the same.
Proof 3 (Angle Side Angle) ASA:
Two angles are the same length so the side in between them is the same.
Proof 4 (Angle Angle Side) AAS:
Two angles are the same size and so is one of the sides.

Use letter notation for sides and angles when explaining.