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 second angle.

• A. ${40}^o$
• B. ${20}^o$
• C. ${50}^o$
• D. ${10}^o$

Answer 1

The correct option is A

${40}^o$

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 $2\times {20}^{\circ }={40}^o$