=1.5
R=2r=3
当r=1.5,h=2时,a=2.5
2a(n/360)=d (a为母线,n为扇形角度,d为底面直径)
则2X2.5(n/360)=3
n=216
S侧=πr²(n/360)=3.14X2.25x0.6=4.239平方厘米
S表=S侧+S底=4.239+πr²=4.239+3.14X2.25=11.304平方厘米
V=1/3S底Xh=1/3x7.065x2=4.71立方厘米
=1.5
R=2r=3
当r=1.5,h=2时,a=2.5
2a(n/360)=d (a为母线,n为扇形角度,d为底面直径)
则2X2.5(n/360)=3
n=216
S侧=πr²(n/360)=3.14X2.25x0.6=4.239平方厘米
S表=S侧+S底=4.239+πr²=4.239+3.14X2.25=11.304平方厘米
V=1/3S底Xh=1/3x7.065x2=4.71立方厘米