Answer:
255π (cm³).
Step-by-step explanation:
1. the initial formula for the required volume is V=V1-V2, where V1=π(r1)²h, V2=π(r2)²h;
h=20m=2000cm, r1=0.5*d1, r2=0.5*d2;
d1=1cm., d2=0.7 cm.
2. the final formula of the required volume is
[tex]V=\frac{ \pi*h}{4} (d_1^2-d_2^2);[/tex]
3. if to substitute the values of d1, d2 and h, then
[tex]V=\frac{ \pi*2000}{4} (1-0.49)=500 \pi*0.51=255 \pi \ (cm^3).[/tex]
