If the radius of the small circle is 2 cm and the radius of the large circle is 3 cm, then the area of the small circle is equal to the area of the large circle.
小圆的半径是2厘米，大圆的半径是3厘米，则小圆的面积是大圆面积的多少．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<gadget id="calculator">12.56 / 28.26</gadget>
<output>0.444444</output>

<result>0.444444</result>