The volume of a cylinder varies jointly with the base (area) and the height. The volume is 40 inches^3 when the base (area) is 6 inches^2 and the height is 20 inches. Find the volume of the cylinder (after finding the variation constant) when the base (area) is 8 inches^2 and the height is 12 inches.

 K = ¹/₃, V = 32in³

Step-by-step explanation:

Volume of s cylinder (V) = πr²h where πr² is the base area.

Now from the question,

V ∞ πr²h

V = kπr²h where k is the constant of proportionality which is also the variation constant.

40 = 6 x 20 x k

40 = 120k and

k   = ⁴⁰/₁₂₀

     = ¹/₃.

Now to find the volume when base area is 8in² and h is 12,

V = 8 x 12 x ¹/₃

V = 32in³