Question

Find smallest of two supplementary angles, if they are in the ratio $7:11$.

• A. $65$
• B. $70$
• C. $75$
• D. $80$

Answer 1

Answer: (B)

$70$

Two angles whose sum is ${180}^o$ are said to be supplementary.

Given two angles are the ratio of $7:11$

Let the two angles be $7x$ and $11x$.

So, $7x+11x={180}^o$

$\Rightarrow 18x={180}^o$

$\Rightarrow x=\frac{180}{18}$

$\Rightarrow x=10$

Therefore, the two angles are $7x={70}^o$ and $11x={110}^o$.