If the diameter of a circle is tripled, how many times will its area be doubled?
一个圆的直径扩大3倍，那么它的面积扩大多少倍．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

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

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

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

<result>9</result>