# Triangles

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.