A cylinder is a square when viewed from the side. The radius of the base of this cylinder is 3 decimeters, what is the height of the cylinder.
一个圆柱体，侧面展开图是正方形．这个圆柱的底面半径是3分米，圆柱的高多少．
<gadget id="calculator">2 * 3.14 * 3</gadget>
<output>18.84</output>

<result>18.84</result>