It is known that the side of the cylinder is a square with a side length of 31.4 meters, what is the radius of the bottom?
已知圆柱体的侧面展开后是一个边长是31.4米的正方形，则底面的半径是多少．
<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

<result>5</result>