Question

The aperture of a camera is formed by $10$ blades. The blades overlap to form a regular decagon. What is the measure of $\angle BAX$?

• A. ${45}^o$
• B. ${36}^o$
• C. ${144}^o$
• D. ${44}^o$

Answer 1

The correct option is B ${36}^o$

Sum of angles of n-sided polygon $=(n-2)\times {180}^o$

Hence, sum of angles of decagon $=(10-2)\times {180}^o$

Since, it is regular decagon so each angle $=\frac{(10-2)\times {180}^o}{10}$

So, $\angle JAB={144}^o$

and $\angle BAX={180}^o-{144}^o={36}^o$