A cylinder has a base diameter of 4 decimeters and a height of 5 decimeters, what is its lateral area in square decimeters?
一个圆柱的底面直径是4分米，高5分米，它的侧面积是多少平方分米．
<gadget id="calculator">3.14 * 4 * 5</gadget>
<output>62.8</output>

<result>62.8</result>