Question

triangle abc has 2 interior angles with measures of 102 and 43 which of the following could be the measure of an exterior angle of triangle abc

Answer 1

What are the options?

Answer 2

The answer is A-78 

The third interior angle = 180 - 102 - 43 = 35 degrees
The measure of exterior angle #1 = 102 + 43 = 145 degrees

The measure of exterior angle #2 = 102 + 35 = 137 degrees
The measure of exterior angle #3 = 43 + 35 = 78 degrees <-- this is one of the 4 choices. 
Therefore 78 degrees could be the measure of an exterior angle of triangle ABC