Question

Three angles together constitute a right angle i.e. ${90}^{\circ }$. One of them is ${30}^{\circ }$, second one is twice the third one. Find the third angle.

• A. ${40}^{\circ }$
• B. ${60}^{\circ }$
• C. ${30}^{\circ }$
• D. ${20}^{\circ }$

Answer 1

The correct option is D

${20}^{\circ }$

Let, third angle be 'x', then second angle will be '2x'.

Sum of all the angles is given to be ${90}^{\circ }$

i.e. x + 2x + ${30}^{\circ }$ = ${90}^{\circ }$

or 3x = ${60}^{\circ }$

or x = ${20}^{\circ }$

So the required angle is ${20}^{\circ }$