After a grenade explodes, the effective killing radius is 15 meters, what is the killing area in square meters?
一种手榴弹爆炸后，有效的杀伤半径是15米，杀伤面积是多少平方米．
<gadget id="calculator">3.14 * 15 * 15</gadget>
<output>706.5</output>

<result>706.5</result>