A cylindrical reservoir with a diameter of 10 meters and a depth of 2 meters. Spread cement around the pool and the bottom of the pool, 2.5 square meters per kilogram of cement, how many kilograms of cement is needed?
一个圆柱形蓄水池，直径10米，深2米．在池的一周及池底抹上水泥，每千克水泥可以抹2.5平方米，需要多少千克水泥？
<gadget id="calculator">3.14 * 10 * 2</gadget>
<output>62.8</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">62.8 + 78.5</gadget>
<output>141.3</output>

<gadget id="calculator">2.5 * 141.3</gadget>
<output>353.25</output>

<result>353.25</result>