Shapes that are exactly the same shape **and **size are **congruent**.

**Triangles**

We have a set of rules which make a** triangle** congruent!

If these rules apply then the triangles are congruent!

**1) Three matching sides (SSS)**

**2) Two matching sides and the angle between them (SAS)**

**3) Two matching angles and a corresponding side (AAS)**

**4) In a right-angled triangle, the hypotenuse and one matching side (RHS)**

Make a note of the four rules and we will look at an example question.

**Example**

The triangles below are congruent.

State the condition that shows they are congruent.

**Answer**

Well, the choices we have are:

*SSS - all 3 sides are the same*

*SAS - 2 matching sides and the angle between*

*AAS - 2 matching angles and a corresponding side*

*RHS - Right angle, hypotenuse and a matching side*

**All the sides are the same - 4 and 4, 5 and 5 and 7 and 7**

So, we can say they are congruent, as the condition is **SSS**

There's a lot to remember here, but you can look back at this introduction at any point by clicking on the red help button on the screen.