If a cylinder has a base diameter of 4 decimeters and a height of 5 decimeters, what is its volume in cubic decimeters?
一个圆柱体的底面直径是4分米，高是5分米，它的体积是多少立方分米．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 * 5</gadget>
<output>62.8</output>

<result>62.8</result>