The measures of two supplementary angles have a ratio of 5 : 4. What is the measure of the larger angle

Supplementary angles add to 180

let x and y represent the two angles

x + y = 180°

and if the ratio is 5:4, we can represent the angles by

x = 5a

y = 4a

5a + 4a = 180°

then solve for a

9a = 180°

a = 20°

x = 5 (20)

y = 4 (20)

so the two angles are

100° and 80°