Question

If two supplementary angles are in the ratio 2 : 7, then the angles are :

• A. ${35}^{\circ },{145}^{\circ }$
• B. ${70}^{\circ },{110}^{\circ }$
• C. ${40}^{\circ },{140}^{\circ }$
• D. ${50}^{\circ },{130}^{\circ }$

Answer 1

Answer: (C)

${40}^{\circ },{140}^{\circ }$

Let the angles be $2x$ and $7x$

Angles are given supplementary

$2x+7x={180}^{\circ }9x={180}^{\circ }x={20}^{\circ }$

So the angles are $2\times {20}^{\circ }={40}^{\circ }$ and $7\times {20}^{\circ }={140}^{\circ }$