(1)3.14×4×5+3.14×（4÷2）²＝62.8+3.14×4＝62.8+12.56＝75.36≈80（dm²)(2)3.14×(4÷2)²×5＝3.14×20＝62.8(dm³)＝62.8(L)62.8×1＝62.8(kg)
