Volume and surface area of a cylinder

1. Sep 7, 2009

Paulo Serrano

1. The problem statement, all variables and given/known data
I need the ratio like in the image below
http://img228.imageshack.us/img228/4015/foiessa.jpg [Broken]
I guess as a function of D.

2. Relevant equations
Volume of a cylinder: pi*r^2*h
Area: 2*pi*r*(h+r)

3. The attempt at a solution

No clue.

Last edited by a moderator: May 4, 2017
2. Sep 7, 2009

Integral

Staff Emeritus
You have expressions for the area and volume, you are told to compute the ratio

$$\frac {Volume} {Area}$$

3. Sep 8, 2009

The area of a cylinder, as far as I remember, is: 2*pi*r*h +(2*pi*r^2)

4. Sep 8, 2009

Now find the the volume, and divide that by area.

V= d^2*pi*h

A= (2*pi*d*h) + (2pi*d^2)

And now write V/A = (d^2*pi*h)/[(2*pi*d*h) + (2pi*d^2)]

I hope I am right, and that it helps! :)

5. Sep 8, 2009

Integral

Staff Emeritus
That is a good start. Now do some simplification.

6. Sep 8, 2009