The formula for the volume of a cylinder is V=πr^2h. Which is volume equals pie * radius squared * height. pie = 3.14. radius is diameter/2, 3.5 in this case, then squared which is 3.5 * 3.5. And the height is 12. You take 3.14, 3.5^2, and 12 then multiply each term. So your substituted equation would be V=3.14(3.5^2)12.
This is how it would go:
V=3.14(3.5^2)12. 3.5^2 = 12.25. - just squared 3.5, that equals 12.25
V=3.14(12.25)12 3.14 * 12.25 = 38.465 - pie times 12.25 equals 38.465
