If the radius of a circle is tripled, how many times is its diameter enlarged?
将一个圆的半径扩大3倍，其直径扩大了多少倍．
<gadget id="calculator">1 * 2</gadget>
<output>2</output>

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

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

<result>3</result>