A square is obtained by unfolding the sides of a cylindrical carton. If the radius of the base of the cylinder is 5 cm, what is its height in cm?
把一个圆柱体纸盒的侧面展开得到一个正方形．如果这个圆柱体纸盒的底面半径5厘米，那么它的高是多少厘米．
<gadget id="calculator">2 * 3.14 * 5</gadget>
<output>31.4</output>

<result>31.4</result>