Congruence (F)

Shapes can be congruent to each other even if one of them has been reflected or rotated, so don’t get caught out by that little trick!

Triangles are a common shape to come up in questions on congruency, and there are 4 different ways to show it. You need to be familiar with each of them.

ASA – Angle, Side, Angle. Show that 2 angles in each triangle are the same, and a corresponding side is the same length.

SAS – Side, included Angle, Side. Show that 2 pairs of corresponding sides are equal, and the angle formed between these 2 sides.

SSS – Side, Side, Side. Show that all 3 pairs of corresponding sides are equal.

RHS – Right-angle, Hypotenuse, Side. This is a special case for right-angled triangles. Show that the hypotenuse and one other side of each triangle is the same.

Remember these three-letter abbreviations, as you can state them as your reasoning when it comes to the exam.