Two angles are supplementary. The ratio of the measure of the smaller angle to that of the larger angle is 5:7. What is the measure of the smaller angle ?

Answer 1

S:L = 5:7

S/L = 5/7

7S = 5L

L = (7/5)S

S+L = 180

(7/5)S + S = 180

(12/5)S = 180

S = (5/12)180 = 5(15) = 75 degrees

L = 180-75 = 105 degrees

75/105 = 5/7