Results 1 to 3 of 3
Like Tree1Thanks
  • 1 Post By Soroban

Math Help - Find the center and radius of a circle (x-h)^2+(y-k)^2=r^2 (completion of square)

  1. #1
    Newbie
    Joined
    May 2012
    From
    Montreal
    Posts
    12

    Unhappy Find the center and radius of a circle (x-h)^2+(y-k)^2=r^2 (completion of square)

    Is this bad? A program indicates that I'm correct for 2/3. What's my mistake?

    I need to find (h,k) and the radius.

    5x^2 -3x +5y^2 -9y -8 =0

    x^2 -3x/5 +y^2 -9y/5 -8/5 =0

    x^2 -3x/5 +(3/10)^2 -(3/10)^2 +y^2 -9y/5 +(9/10)^2 -(9/10)^2 -8/5 =0

    (x -3/10)^2 -(3/10)^2 +(y -9/10)^2 -(9/10)^2 -8/5 =0

    (x -3/10)^2 + (y -9/10)^2 -(3/10)^2 -(9/10)^2 -160/100 =0

    (x -3/10)^2 +(y -9/10)^2 -9/100 -81/100 -160/100 =0

    (x -3/10)^2 +(y -9/10)^2 = (250/100)^(1/2)

    h: 3/10
    k: 9/10
    r: (5/2)^(1/2)

    Please help.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,660
    Thanks
    600

    Re: Find the center and radius of a circle (x-h)^2+(y-k)^2=r^2 (completion of square)

    Hello, SillyMath!

    I see nothing wrong with your work.
    Perhaps the program didn't like your radius?

    . . r \:=\:\sqrt{\frac{5}{2}} \:=\:\frac{\sqrt{10}}{2}
    Thanks from SillyMath
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    May 2012
    From
    Montreal
    Posts
    12

    Re: Find the center and radius of a circle (x-h)^2+(y-k)^2=r^2 (completion of square)

    Thank you but it still won't take it.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: March 12th 2011, 01:24 AM
  2. Replies: 7
    Last Post: March 15th 2010, 04:10 PM
  3. Find the center and radius of circle
    Posted in the Geometry Forum
    Replies: 3
    Last Post: December 28th 2009, 03:45 PM
  4. Replies: 4
    Last Post: September 11th 2008, 09:20 AM
  5. Find Center, Radius and Graph Each Circle
    Posted in the Geometry Forum
    Replies: 5
    Last Post: January 15th 2007, 03:59 PM

Search Tags


/mathhelpforum @mathhelpforum