After a grenade explodes, the radius of the effective killing area is 6 meters. How many square meters is the effective killing area?
一种手榴弹爆炸后，有效杀伤范围的半径是6米，有效杀伤面积是多少平方米？
<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

<result>113.04</result>