Expand the side of a cylinder along the height to get a square. The side length of this square is 31.4 decimeters. What is the volume of this cylinder in cubic decimeters?
把一个圆柱的侧面沿着高展开，得到一个正方形，这个正方形的边长是31.4分米，这个圆柱体的体积是多少立方分米．
<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 * 31.4</gadget>
<output>2_464.9</output>

<result>2_464.9</result>