Question

Two supplementary angles are in the ratio $5:7$. Find the smallest angle.

$1^{st}$ angle $=$ $\frac{5}{12}\times {180}^o$ and $2^{nd}$ angles $=$ $\frac{7}{12}\times {180}^o$

• A. $80$
• B. $75$
• C. $65$
• D. $90$

Answer 1

The correct option is B $75$

Sum of supplementary angles $={180}^o$

Given two supplementary angles are in the ratio $5:7$.

$1^{st}$ angle $=\frac{5}{12}\times {180}^o=5\times 15={75}^o$

$2^{nd}$ angle $=\frac{7}{12}\times {180}^o=7\times 15={105}^o$