Question

A side of the triangle below has been extended to form an exterior angle of 77º. Findthe value of x

Answer 1

The exterior angle (the one with a measure of 77°) and angle x are supplementary angles since the first is next to angle x and are located on the same line, supplementary angles add up to 180°, then we can calculate the measure of x by means of the following formula:

x + 77° = 180°

x + 77° - 77° = 180° - 77°

x + 0 = 103°

x = 103°

Then, x equals 103°