Expand the side of a cylinder to get a square. The circumference of the bottom of the cylinder is 31.4dm. What is the volume of the cylinder in dm**3.
把一个圆柱体侧面展开，得到一个正方形，这个圆柱体底面周长是31.4dm，圆柱体的体积是多少dm**3．
<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 * 31.4</gadget>
<output>2_464.9</output>

<result>2_464.9</result>