Question

What is the value of h?

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

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.

Answer 1

Interior and exterior at a vertex are supplementary, so
(3h + 18) + 15h = 180
18h + 18 = 180
18h = 162
h = 9

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