In the diagram, the centre of the circle is $O$. The area of the shaded region is $20 \%$ of the area of the circle. The value of $x$ is
(A) 18
(B) 45
(C) 60
(D) 72
(E) 90

![](https://cdn.mathpix.com/cropped/2024_04_20_e85ef69091c57cb633f3g-086.jpg?height=284&width=274&top_left_y=1533&top_left_x=1294)
Since the shaded area is $20 \%$ of the area of the circle, then the central angle should be $20 \%$ of the total possible central angle.

Thus, $x^{\circ}=\frac{20}{100}\left(360^{\circ}\right)$ or $x=\frac{1}{5}(360)=72$.

ANSWER: (D)