Question

In the figure above, what is the value of $y$?

• A. ${40}^o$
• B. ${45}^o$
• C. ${50}^o$
• D. ${60}^o$
• E. ${72}^o$

Answer 1

Answer: (D)

${60}^o$

From the figure

$y^{\circ }=2x^{\circ }$ (vertically opposite angles)

$\Rightarrow x=\frac{y}{2}$

Now $y^{\circ }+4x^{\circ }={180}^{\circ }$ (Sum of adjacent angles on straight line is supplementary)

Substi

$y+4\times \frac{y}{2}={180}^{\circ }\Rightarrow y+2y={180}^{\circ }\Rightarrow 3y={180}^{\circ }\Rightarrow y={60}^{\circ }$

So option $D$ is correct.