The lateral expansion of a cylinder is a square, the radius of the base of the cylinder is 0.2 decimeters, what is the height of the cylinder in centimeters.
一个圆柱的侧面展开是正方形，圆柱的底面半径是0.2分米，圆柱的高是多少厘米．
<gadget id="calculator">3.14 * 0.2 * 2 * 10</gadget>
<output>12.56</output>

<result>12.56</result>