Congruence and similarity · Year 9

In Year 9 you learn: congruent triangles.

Congruent shapes are identical in shape and size. Similar shapes have the same shape but may be different sizes: all their lengths are in the same ratio (the scale factor), and their angles are equal.

Key facts

• Triangles are congruent if they match by SSS, SAS, ASA (or AAS) or RHS. AAA is not enough.

Other years

• Congruence and similarity · Year 10
• Congruence and similarity · Year 11