Results 1 to 2 of 2

Math Help - Surface area of cube

  1. #1
    Junior Member
    Joined
    Aug 2008
    From
    India
    Posts
    44

    Surface area of cube

    Two cubes have volumes in the ratio 1:27.the ratio of their surface areas is
    (a)1:3
    (b)1:8
    (c)1:9
    (d)1:18
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,547
    Thanks
    1418
    Quote Originally Posted by devi View Post
    Two cubes have volumes in the ratio 1:27.the ratio of their surface areas is
    (a)1:3
    (b)1:8
    (c)1:9
    (d)1:18
    For a cube of 1 unit length, it's volume is 1. For a cube of side length 3 units, its volume is 3^3=27units^3.

    So their side lengths are in the ratio 1:3.

    The surface area of a cube is given by 6\times length^2.

    So the surface areas will be 6 and 54. Since 54 is 9 times 6, the ratio of their surface areas will be 1:9.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Surface area of solid cube
    Posted in the Algebra Forum
    Replies: 1
    Last Post: November 4th 2011, 04:04 PM
  2. Replies: 0
    Last Post: October 8th 2009, 12:05 PM
  3. Surface Area of a Truncated cube
    Posted in the Geometry Forum
    Replies: 1
    Last Post: May 3rd 2009, 08:57 PM
  4. Replies: 2
    Last Post: March 30th 2008, 01:54 PM
  5. Cube volume and surface area help!
    Posted in the Geometry Forum
    Replies: 2
    Last Post: January 7th 2007, 02:49 PM

Search Tags


/mathhelpforum @mathhelpforum