Solution: Suppose this batch of cement has X tons. Then Party A delivers 7/ 15x+ 18, and the cement delivered by Party B is x-7/ 15x- 18.

x-7/ 15x- 18:7/ 15x+ 18 = 1:2

2(x-7/ 15x- 18)= 7/ 15x+ 18

2x- 14/ 15x-36 = 7/ 15x+ 18

2x- 14/ 15x-7/ 15x = 18+36

3/5x=54

x=54×5/3

X=90 Let the price of this commodity be1; The price is1.30;

The 20% discount is 1.30*80%= 1.04.

104÷ 1.04= 100;

Therefore, the cost of goods is 100 yuan;

After-sales revenue: 104- 100=4 yuan.

So the volume height of 4 yuan's solution round steel is X. ..

4/9X=8

X= 18

V=πr squared ×

Square of π× 5× 18

=450π

= 14 13cm cube