Question

The measure of an angle that is four times its supplement is,

• A. $36°$
• B. $144°$
• C. $16°$
• D. $64°$

Answer 1

The correct option is B

$144°$

The explanation for the correct option.

When the sum of two angles is $180°$, then the angles are known as supplementary angles.

Let us consider that angle be $y°$.

$\therefore$ Supplementary angle$=(180-y)°$

According to the question,

$$\begin{gathered} \therefore y=4(180-y) \\ \Rightarrow y=720-4y \\ \Rightarrow y+4y=720 \\ \Rightarrow 5y=720 \\ \Rightarrow y=\frac{720}{5} \\ \Rightarrow y=144° \end{gathered}$$

Thus, the required angle is $144°$.

Hence, the option $B$is correct.