Congruent-Triangles Aqa Foundation

Congruent triangles

What are congruent triangles?

• Two triangles are congruent if they are the same size and shape

  • Although they may be reflections, translations or rotations of each other

• All three angles and all three sides must be the same in both triangles

How do I prove that two triangles are congruent?

• We only need to show that 3 of the 6 things are the same for both triangles

  • as long as they are the right three!

• To do this we must use one of the 5 standard tests

Name	Description	Diagram
SAS Side Angle Side	Two sides and the angle between them
ASA Angle Side Angle	Two angles and the side between them
AAS Angle Angle Side	Any two angles and any side
SSS Side Side Side	All three sides
RHS Right-angle Hypotenuse Side	The hypotenuse and any other side for a right-angled triangle