A cylinder with a side area of 12.56 square decimeters and a height of 4 decimeters, what is its volume?
一个圆柱侧面积是12.56平方分米，高是4分米，它的体积是多少．
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">12.56 / 4 / 6.28</gadget>
<output>0.5</output>

<gadget id="calculator">0.5 ** 2</gadget>
<output>0.25</output>

<gadget id="calculator">3.14 * 0.25 * 4</gadget>
<output>3.14</output>

<result>3.14</result>