Question

某县重新维修排水管道,需要下面的水泥管3200根,每根水泥管长2米,制作这些水泥管共需要多少?题在下面

Answer 1

90cm=0.9m

120cm=1.2m

3200×[π×(1.2÷2)²-π×(0.9÷2)²]×2

=6400x(0.6²-0.45²)π

=6400x(0.6+0.45)x(0.6-0.45)xπ

=6400x1.05x0.15xπ

=1008π

≈3165.12m³