谷物的体积不变:
(4/2)²πH=3²π*0.9/3,
H=2.7/4=0.675(米);
一个圆柱和圆锥的底面周长比是2：3,体积比是8：5,圆锥与圆柱高比是多少?
圆锥与圆柱高H1,H2,底面周长C1,C2,底面半径C1=2πR1,C2=2πR2,
C2:C1=2:3
2πR2:2πR1=2:3
R2:R1=2:3
体积V1,V2:
V2:V1=8:5,
R2²πH2:R1²πH1/3=8:5,
R2²H2:R1²H1/3=8:5,
(R2/R1)²(H2:H1)=8:15
(2/3)²(H2:H1)=8:15
H2:H1=8/15*9/4=6:5,
H1:H2=5:6