Question

A triangle with exterior angles is shown. The bottom right angle of the triangle is (3 h + 18) degrees. The bottom right exterior angle is (15 h) degrees.
What is the value of h?

h = 1.5
h = 9
h = 10
h = 13.5

Answer 1

Interior and exterior at the same vertex form a linear pair, so they sum to 180°:
(3h + 18) + 15h = 180
18h + 18 = 180
18h = 162
h = 9

Check: interior = 3(9)+18 = 45°, exterior = 15(9) = 135°, sum = 180°.