A triangle is a polygon with 3 sides.

The interior angles of any triangle will add up to 180°.

**Area of a Triangle**

To find the **area of a triangle**, use this formula:

$$A = \frac{b × h}{2}$$

**Equilateral Triangle**

- All sides the same length.
- All angles the same size. (Each one is 60°.)

**Isosceles Triangle**

- One line of symmetry.
- Two sides the same length.
- Two angles the same size.

**Scalene Triangle**

- All sides different.

**Right-Angled Triangle**

- Contains a right angle.