# Congruent shapes

Two shapes that are the same size and the same shape are congruent.

Shapes A, B, E and G are congruent. They are identical in size and shape.

## Congruent triangles

For two triangles to be congruent, one of 4 criteria need to be met.

The three sides are equal (SSS: side, side, side)

Two angles are the same and a side is the same (ASA: angle, side, angle)

Two sides are equal and the angle between the two sides is equal (SAS: side, angle, side)

A right angle, the and a corresponding side are equal (RHS, right angle, hypotenuse, side)

### Example 1

State whether the two triangles are congruent. Give a reason to support your answer.

Yes - SSS, the three sides are equal.

### Example 2

State whether the two triangles are congruent. Give a reason to support your answer.

Yes - RHS.

Question

State whether the two triangles are congruent. Give a reason to support your answer.

No - in the left hand diagram the 7 cm length is between the angles 40° and 60°. In the right hand diagram it is not.