After a grenade explodes, the radius of the effective killing area is 8 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8米，有效杀伤面积是多少平方米？
<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">3.14 * 64</gadget>
<output>200.96</output>

<result>200.96</result>