Question

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

• A. ${120}^o$
• B. ${125}^o$
• C. ${110}^o$
• D. ${90}^o$

Answer 1

The correct option is A ${120}^o$

Option $\left(A\right)$ is correct.

Two supplementary angles are in the ratio $1:2$

So, let two angles be $x$ and $2x$

Given that, angles are supplementary

$\therefore x+2x={180}^o$

$\Rightarrow 3x=180$

$\Rightarrow x=\frac{{180}^o}{3}$

$\Rightarrow x={60}^o$

Therefore, bigger angle is $2x={120}^{\circ }.$