The radius of the small circle is (1/4) of the radius of the large circle, and the area of the small circle is equal to the area of the large circle.
小圆半径是大圆半径的(1/4)，小圆面积是大圆面积的多少．
<gadget id="calculator">1 / 16</gadget>
<output>1/16 = around 0.0625</output>

<result>1/16 = around 0.0625</result>