Results 1 to 3 of 3

Math Help - very confusing homework

  1. #1
    Newbie
    Joined
    Mar 2008
    Posts
    12

    Cool very confusing homework

    What is the approximate area of a segment of a circle with a radius 12 meters if the length of the chord is 20 meters? Round your answer to the nearest whole number.


    I started but i could not solve for theta given as:

    20=24sin(theta/2)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member topher0805's Avatar
    Joined
    Jan 2008
    From
    Vancouver
    Posts
    336
    20 = 24sin\left(\frac {\theta}{2}\right)

    sin\left(\frac {\theta}{2}\right) = \frac {5}{6}


    Where did you get that formula from?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member topher0805's Avatar
    Joined
    Jan 2008
    From
    Vancouver
    Posts
    336



    Notice that I have divide the isosceles triangle in half, creating two right angle triangles. We know that the hypotenuse is 12 and that one side is 10 so all we have to do is find the angle we need and multiply it by 2.

    So we have:

    \sin {\theta} = \frac {10}{12}

    \sin {\theta} = \frac {5}{6}

    Use the arcsin function to solve for \theta and then plug that into this formula:

    \frac {1}{2}r^2\left(\frac {\pi}{180}\theta - \sin {\theta}\right) If you are using degrees

    or

    \frac {1}{2}r^2\left(\theta - \sin {\theta}\right) If you are using radians.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. confusing >.<
    Posted in the Algebra Forum
    Replies: 4
    Last Post: June 20th 2009, 10:28 PM
  2. Replies: 5
    Last Post: September 22nd 2008, 07:44 PM
  3. this is so confusing...
    Posted in the Algebra Forum
    Replies: 2
    Last Post: August 6th 2008, 09:19 PM
  4. Confusing homework questions HELP!!
    Posted in the Calculus Forum
    Replies: 4
    Last Post: May 29th 2008, 12:28 AM
  5. so confusing!
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 23rd 2006, 04:22 PM

Search Tags


/mathhelpforum @mathhelpforum