The side of a cylinder is unfolded to obtain a rectangle with a length of 12.56cm and a width of 3cm. If the height of the cylinder is 3cm, what is the radius of its bottom in cm?
一个圆柱的侧面展开后得到一个长方形，长是12.56cm，宽是3cm，若这个圆柱的高是3cm，则它的底面半径是多少cm．
<gadget id="calculator">12.56 / 3.14 / 2</gadget>
<output>2</output>

<result>2</result>