If the diameter of a circle is 4 cm, if its diameter is increased to 12 cm, the area of the circle now is how many times the area of the original circle.
一个圆的直径是4厘米，现在把他的直径增加到12厘米，现在圆的面积是原来圆的面积的多少倍．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

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

<result>9</result>