If we extend any side of the triangle then we get an exterior angle.

- An exterior angle must form a linear pair with one of the interior angles of the triangle.
- There are only two exterior angles possible at each of the vertices.

An Exterior angle of a triangle will always be equal to the sum of the two opposite interior angles of the triangle.

Here, ∠d = ∠a + ∠b

This is called the Exterior angle property of a triangle.

**Example**

Find the value of “x”.

**Solution**

x is the exterior angle of the triangle and the two given angles are the opposite interior angles.

Hence,

x = 64°+ 45°

x = 109°

Login

Accessing this course requires a login. Please enter your credentials below!