help find cylinder height, given radius, surface area

[Guest]

Im confused the problem says

Use the following relationship:The lateral surface area of a cylinder varies jointly as the radius and height of the cylinder.A cylinder with radius 0.8 in. and height 6 in. has a lateral surface area of 30.2 in^2.

find the height of a cylinder with radius 1.5 in. and lateral surface area 74.4 in^2.

 

[TchrWill]

Re: help!

Im confused the problem says

Use the following relationship:The lateral surface area of a cylinder varies jointly as the radius and height of the cylinder.A cylinder with radius 0.8 in. and height 6 in. has a lateral surface area of 30.2 in^2.

find the height of a cylinder with radius 1.5 in. and lateral surface area 74.4 in^2.

A = PiR^2h
A = 74.4
R = 1.5
h = 74.4/(3.14(1.5^2))