Question

Two adjacent angles on a straight line are in the ratio 5 : 4. Find the measure of each one of these angles.

Answer 1

Given, the ratio of two adjacent angles on a straight line = 5 : 4

So, one angle = 5x and the other angle = 4x

We know that, two adjacent angles on a straight line always forms a linear pair.

⇒5x + 4 x = 180°

⇒9x = 180°

⇒ x = 20°

Therefore, one angle = 5x = 5 × 20° = 100°

and other angle = 4x = 4 × 20° = 80°