Divide the bottom surface of a cylinder into several sectors on average, cut along the height and assemble them into an approximate cuboid. The perimeter of the cuboid is 41.4 cm and the height is 5 cm. Find its volume.
把一个圆柱底面平均分成若干个扇形，沿高切开拼成一个近似长方体，这个长方体的底周长是41.4厘米，高是5厘米，求它的体积．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25 * 5</gadget>
<output>392.5</output>

<result>392.5</result>