If the area of a circle is 64cm**2 after the circumference of a circle is enlarged by 4 times, what is the area of the original circle?
如果把一个圆的周长扩大4倍后的面积是64cm**2，那么原来圆的面积是多少．
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">64 / 16</gadget>
<output>4</output>

<result>4</result>