Results 1 to 5 of 5

Math Help - Area of an oblique triangle question

  1. #1
    Newbie
    Joined
    Sep 2012
    From
    UK
    Posts
    20

    Area of an oblique triangle question

    Hello,
    I need help with this question:
    "There is a triangle OAB. The length of AO is 10m and AOB has an angle of 0.8c. This triangle also has an arc between points A and B."
    Find the area of the triangle OAB
    Find the area of the sector OAB

    I have drawn the triangle to its correct description, see the attached image.

    I have tried using the formula for the area of the sector 0.5r2θ, but I got the answer to be 2193. This might be right, just seemed too big. But I do not know the formula for the area of the triangle! (I suppose this triangle is different to the formula 0.5xbxh)
    Could you please help me work out how to find the area of this triangle?

    Thanks in advance
    Dan
    Attached Thumbnails Attached Thumbnails Area of an oblique triangle question-imag0036.jpg  
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1

    Re: Area of an oblique triangle question

    Quote Originally Posted by Danthemaths View Post
    Hello,
    I need help with this question:
    "There is a triangle OAB. The length of AO is 10m and AOB has an angle of 0.8c. This triangle also has an arc between points A and B."
    Find the area of the triangle OAB
    Find the area of the sector OAB

    I have drawn the triangle to its correct description, see the attached image.
    This webpage will help you.

    I cannot help you because I have no idea what 0.8^c could mean.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,408
    Thanks
    1294

    Re: Area of an oblique triangle question

    Quote Originally Posted by Plato View Post
    This webpage will help you.

    I cannot help you because I have no idea what 0.8^c could mean.
    It means 0.8 radians... C is the symbol for radians, it stands for "number of lengths of the radius on the Circumference".

    I suppose we're assuming that it's a circular arc, which means OB = OA, correct?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Sep 2012
    From
    UK
    Posts
    20

    Re: Area of an oblique triangle question

    Yes OB=OA. And 0.8 radians = 57.3 degrees
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,408
    Thanks
    1294

    Re: Area of an oblique triangle question

    If the angle is measured in radians, the area of the triangle can be found using \displaystyle \begin{align*} A = \frac{1}{2}ab\sin{(C)} \end{align*} and the area of a sector can be found using \displaystyle \begin{align*} A = \frac{1}{2}r^2\theta \end{align*}.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Area of triangle(s) question
    Posted in the Advanced Math Topics Forum
    Replies: 1
    Last Post: January 9th 2013, 12:47 PM
  2. Area of a triangle Question
    Posted in the Algebra Forum
    Replies: 6
    Last Post: May 27th 2012, 10:09 AM
  3. Replies: 2
    Last Post: September 7th 2010, 05:16 PM
  4. Replies: 7
    Last Post: July 10th 2010, 05:54 AM
  5. increase in rate of area of triangle question
    Posted in the Calculus Forum
    Replies: 5
    Last Post: November 12th 2006, 05:29 PM

Search Tags


/mathhelpforum @mathhelpforum