用等体积法来考虑,熔铸前后铁块的体积不变熔铸前:V=15.7 x 12 x 5 = 942熔铸后:设底面半径为R,则2∏R=2 ,得R=1/∏ V=∏ * R * R * h = 942解得:h = 942 ∏ = 942 x 3.14 = 2957.88
v=15.7*12*5=942 R=2/2*3.14v(铁棍)=v(铁块)=地面积*高=3.14*R^2*L L=2957.88