A cylinder and a cone with the same base and height, the sum of their volume is 314 cubic decimeters, and the height is 3 decimeters, what is the radius of the cylinder?
等底等高的一个圆柱体和圆锥体，它们的体积和是314立方分米，高是3分米，那么圆柱体的半径是多少．
<result>5</result>