The radius of the circular lawn is 12 meters, what is the area of the circular lawn?
圆形草地的半径是12米，这圆形草地面积是多少？
<gadget id="calculator">12 ** 2</gadget>
<output>144</output>

<gadget id="calculator">3.14 * 144</gadget>
<output>452.16</output>

<result>452.16</result>