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 decimeters.
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，圆柱的高是多少分米．
<gadget id="calculator">3.14 * 2 * 0.2</gadget>
<output>1.256</output>

<result>1.256</result>