A cylindrical aluminum can is being constructed to have a height h of 4 inches. If the can is to have a volume of 36 cubic​ inches, approximate its radius r.​

Question

A cylindrical aluminum can is being constructed to have a height h of 4 inches. If the can is to have a volume of 36 cubic​ inches, approximate its radius r.​ 

Answer 1

The formula for the volume of a cylinder is v = πr²*h.

We have been told that the volume is supposed to be 36 and the height is 4.

If we substitute in those values our formula becomes:

36 = πr²*4 Now we need to solve for the radius

36/4 = πr²*4/4 Divide both sides by 4

8 = πr²

8/π = πr²/π Divide both sides by π

8/π = r²

√(8/π) = √(r²) Take the square root of both sides

±1.6 ≈ r

Since a radius must be positive the answer is approximately 1.6 inches.

Answer 2

Use the formula for the volume of a cylinder with the given height and volume to solve for the radius.

V=πr²h

Remember to take the square root to solve for r.

SQRT(V/(πh))=r

Check the formula and just plug in the numbers

Give it a try.