Question

Could someone plz help with number 4 ? Thanks

Answer 1

255π (cm³).

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

`V=( \pi*h)/(4) (d_1^2-d_2^2);`

3. if to substitute the values of d1, d2 and h, then

`V=( \pi*2000)/(4) (1-0.49)=500 \pi*0.51=255 \pi \ (cm^3).`