The diameter of the base of a cylinder is 2 decimeters, and the lateral expansion is a square. What is the height of the cylinder?
一个圆柱的底面直径是2分米，侧面展开是正方形，这个圆柱的高是多少．
<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<result>6.28</result>