Expand the sides of a cylinder to get a square. The height of the cylinder is 31.4 decimeters. What is the volume of the cylinder?
把一个圆柱体的侧面展开得到一个正方形，这个圆柱体的高是31.4分米，圆柱体的体积是多少．
<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 * 31.4</gadget>
<output>2_464.9</output>

<result>2_464.9</result>