Question

Help!!!!!! The volume of a cylinder varies jointly with the square of its radius and with its height: V=kr2h Cylinder A has a volume of 254.34 cubic inches and has a radius of 3 inches and a height of 9 inches. What is the volume of cylinder B, which has a radius of 4 inches and a height of 5 inches?

Select one:
a. 3.14 cubic inches
b. 62.8 cubic inches
c. 251.2 cubic inches
d. 188.4 cubic inches

Answer 1

For clarity, please use " ^ " to indicate exponentiation: V=k*r^2*h

Our first task is to determine the value of the constant of proportionality, k. Subst. the given info:

V 254.34 in^3

V=k*r^2*h => k = ----------- = ------------------- = 3.14, which is approx pi

r^2*h 3^2* 9

then our formula becomes:

V = π*r^ 2*h

and if r= 4 and h =5, then the volume is V = π(16)(5) = 80π in^2.