If the sides of a cylinder are unfolded to form a square, the diameter of the base of the cylinder is 2 decimeters, what is its height in decimeters.
一个圆柱的侧面展开后得到一个正方形，圆柱的底面直径是2分米，它的高是多少分米．
<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<result>6.28</result>