If a cone has a base of radius r and a height of r, then how many times the volume of a cylinder with a base of radius r and a height of 2r is the volume of the cone.
如果一个圆锥的底面半径与高都为r，那么底面半径为r、高为2r的圆柱体体积是这个圆锥体积的多少倍．
<result>6</result>