直径20.3，那么底面积3.1416*10.15^2=323.6555m^2于是高为4900/323.6555=15.1396m周长3.1416*20.3=63.7745m侧面积63.7745*15.1396=965.5201m^2表面积=323.6555*2+965.5201=1612.8311m^2
