Question

Two supplement angles are in the ratio $2:7$. Find the measure of the angles.

Answer 1

Let the angle be $\theta$ then other be $180-\theta$

They are in ratio $=2:7$

$2\theta =7(180-\theta )$

$\begin{array}{c}\Rightarrow 2\theta =7\times 180-7\theta \\ \Rightarrow 7\theta +2\theta =7\times 180\\ \Rightarrow 9\theta =7\times 180\\ \Rightarrow \theta =\frac{7\times 180}{9}=140\end{array}$

Then,

The angle be $\Rightarrow \theta =140$

& $\left(180-\theta \right)={40}^0$