Results 1 to 2 of 2

Thread: cyclinder

  1. #1
    Junior Member
    Mar 2008


    I need help
    Attached Files Attached Files
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Feb 2007
    New York, USA
    Quote Originally Posted by jwein4492 View Post
    I need help
    People hate opening attachments here. so you would do well in the future not to use them.

    think of breaking the cylinder in pieces. the ends are circles, and we know the area for circles, so that is good. as for the cylinder, we can cut in along the length and flatten it so that it s a rectangle. the length will be the circumference of the circle and the width will be $\displaystyle a$

    so we get, the surface area is given by:

    $\displaystyle A = \underbrace{ \pi r^2 + \pi r^2}_{\mbox{Area of both ends}} +\underbrace{ 2 \pi r a}_{\mbox{Area of the cylinder without the ends}} = 2 \pi r (r + a)$

    i hope you see why. here, r is the radius, which is b/2 since b is the diameter
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: Feb 27th 2014, 07:17 AM
  2. volume of cyclinder
    Posted in the Geometry Forum
    Replies: 1
    Last Post: Dec 10th 2008, 07:21 AM
  3. cyclinder
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: Mar 8th 2008, 09:48 PM
  4. Replies: 3
    Last Post: Oct 25th 2007, 06:55 PM

Search Tags

/mathhelpforum @mathhelpforum