Question

In the figure below, x = ${30}^{\circ }$. The value of $3y$ is ___.

• A. ${60}^{\circ }$
• B. ${180}^{\circ }$
• C. ${120}^{\circ }$
• D. ${40}^{\circ }$

Answer 1

The correct option is C ${120}^{\circ }$

Given, x = ${30}^{\circ }$,
So, 2x = ${60}^{\circ }$

Also, 2x + 3y = ${180}^{\circ }$ (Angles on a straight line)

Replacing 2x in the above equation by ${60}^{\circ }$, we have
${60}^{\circ }$ + 3y = ${180}^{\circ }$

$⟹$ 3y = ${120}^{\circ }$