If you draw a picture with the legs of a compass 4 cm apart, what is the area of the circle in square centimeters?
把圆规两脚叉开4厘米画图，所画出的圆面积是多少平方厘米．
<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<result>50.24</result>