Question

A side of the triangle below has been extended to form an exterior angle of 165º. Find

the value of c.
165
111°

Answer 1

x + 165 = 180

180 - 165 = 15

x=15

Answer 2

x = 15

Explanation:

Interior angles and their exterior angles make a supplementary angle meaning they have a sum of 180°. Knowing this, we can make an equation to solve for x.

x + 165 = 180

x = 15