A cylindrical metal pipe has a diameter of 20 millimeters and a height of 21 millimeters. A cylindrical hole cut out of the center has a radius of 6 millimeters. Which expressions represent the volume of metal needed, in cubic millimeters, to make the pipe? Check all that apply. 21π(10)2 – 21π(6)2 π(20)2(21) – π(6)2 2,100π – 756π 7,644π
1,344

We have been given that a cylindrical metal pipe has a diameter of 20 millimeters and a height of 21 millimeters. A cylindrical hole cut out of the center has a radius of 6 millimeters.

We will use volume of cylinder formula to solve our given problem.

[tex]\text{Volume of cylinder}=\pi r^2h[/tex], where,

r = Radius of cylinder,

h = height of cylinder.

The volume of the cylinder will be equal to volume of cylinder with radius of 10 mm (20/2) minus volume of cylinder with radius of 6 mm.

[tex]\text{Volume of pipe}=\pi*10^2*21-(\pi*6^2*21)[/tex]

Therefore, option A is the correct choice.

[tex]\text{Volume of pipe}=\pi*100*21-(\pi*36*21)[/tex]

[tex]\text{Volume of pipe}=2100\pi-756\pi[/tex]

Therefore, option C is the correct choice as well.

ewomazinoade ewomazinoade · Answer 2 · 2022-04-25T16:59:52+02:00

The expression that represents the volume of the metal needed to make the pipe is 21π(10)² – 21π(6)².

What is the volume of the metal needed to make the pipe ?

The volume of the metal needed to make the pipe is the difference between the volume of the cylindrical pipe and the volume of the hole.

Volume of a cylinder = πr²h

Where :

π = pi
r = radius = diameter / 2
h = height

= 21π(10)² – 21π(6)².

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