Draw a sector in a circle with a central angle of 90°, what fraction of the area of the sector is the area of the entire circle? How many
在一个圆内画一个圆心角是90°的扇形，这个扇形的面积是整个圆面积的几分之几？多少
<gadget id="calculator">90 / 360</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>