Question

In a right angled triangle, if one angle is ${20}^{\circ }$, then its third angle is

• A. ${40}^{\circ }$
• B. ${70}^{\circ }$
• C. ${60}^{\circ }$
• D. ${90}^{\circ }$

Answer 1

The correct option is B ${70}^{\circ }$

Given, Triangle is right angled and one angle = ${20}^{\circ }$

We need to find the third angle.

Therefore,

$\text{Third angle}={180}^{\circ }-({90}^{\circ }+{20}^{\circ })$

$={180}^{\circ }-{110}^{\circ }$

$={70}^{\circ }$

Hence the third angle $={70}^{\circ }$