Question

If two supplementary angles are in the ratio 1 : 2, then the bigger angle is 

(a) 120° (b) 125° (c) 110° (d) 90°

Answer 1

(a) 120^o

We know that, when the sum of the measures of two angles is 180^o, the angles are called supplementary angles.

Let us assume two angle be 1x and 2x.

1x + 2x = 180^o

3x = 180^o

x = 180^o/3

x = 60^o

Then the bigger angle is 2x = 2 × 60^o = 120^o