The height of a cylinder is 5 centimeters, and its lateral expansion is a rectangle with a length of 31.4 centimeters. What is the volume of this cylinder in cubic centimeters?
一个圆柱的高是5厘米，侧面展开是一个长为31.4厘米的长方形，这个圆柱体积是多少立方厘米？
<gadget id="calculator">31.4 / 3.14 / 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">78.5 * 5</gadget>
<output>392.5</output>

<result>392.5</result>