假设圆椎底面直径d，则圆柱底面直径为3d，圆柱圆椎的高都为h那么圆椎的体积=1/3*(d/2)^2*3.14*h=(1/12)*3.14*d^2*h圆柱的体积=(3d/2)^2*3.14*h=(9/4)*3.14*d^2*h圆椎的体积/圆柱的体积=[(1/12)*3.14*d^2*h]/[(9/4)*3.14*d^2*h] =(1/12)/(9/4)=1/27
