The diameter of a circular fish pond is 20 meters. If 15 fish fry are put in on average per square meter of water surface, how many fish fry should be put in this fish pond?
一个圆形养鱼池的直径是20米，如果平均每平方米水面投放15尾鱼苗，那么这个养鱼池一共要投放鱼苗多少尾？
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">100 * 3.14 * 15</gadget>
<output>4_710</output>

<result>4_710</result>