When making a fan-shaped statistical chart, what is the central angle of the fan-shaped circle that occupies 25% of the area of the circle?
制作扇形统计图时，占圆面积25%的扇形圆心角是多少度．
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">360 * (1/4)</gadget>
<output>90</output>

<result>90</result>