Li Village plans to build a cylindrical reservoir with a bottom diameter of 8m and a depth of 2.5m. The inner wall and bottom of the pond are covered with cement, 3kg of cement is used per square meter. How many kilograms of cement are needed in total?
李村计划建一个圆柱形蓄水池，水池底面直径是8m，深是2.5m，把水池的内壁和底面抹上水泥，每平方米用水泥3kg，一共需要水泥多少千克？
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<gadget id="calculator">3.14 * 8 * 2.5</gadget>
<output>62.8</output>

<gadget id="calculator">50.24 + 62.8</gadget>
<output>113.04</output>

<gadget id="calculator">113.04 * 3</gadget>
<output>339.12</output>

<result>339.12</result>