Results 1 to 2 of 2

Math Help - arof an isosceles triangle

  1. #1
    seller299
    Guest

    arof an isosceles triangle

    how do you derermine the area of an isosceles triangle
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,830
    Thanks
    123
    Quote Originally Posted by seller299 View Post
    how do you derermine the area of an isosceles triangle
    Hello,

    an isosceles triangle is divided into 2 right triangles by an altitude.

    If the length of a side of the isosceles triangle is a you can calculate the height by the Pythagorean theorem:

    a^2 = \left(\frac12 \cdot a\right)^2 + h^2~\implies~h=\frac12 \cdot a \cdot \sqrt{3}

    The area of a triangle is calculated by:

    A = \frac12 \cdot s \cdot h_s where s is the base side and h_s is the height of the triangle perpendicular to s. Plug in the values you know about the isosceles triangle:

    A_{isosceles \ triangle}=\frac12 \cdot a \cdot \frac12 \cdot a \cdot \sqrt{3} = \frac14 \cdot a^2 \cdot \sqrt{3}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. value of x in an isosceles triangle
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: April 6th 2011, 09:43 AM
  2. Isosceles Triangle
    Posted in the Geometry Forum
    Replies: 1
    Last Post: January 24th 2011, 01:29 AM
  3. Isosceles triangle
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: February 28th 2010, 06:44 AM
  4. Isosceles triangle
    Posted in the Geometry Forum
    Replies: 1
    Last Post: November 11th 2008, 10:41 AM
  5. Replies: 27
    Last Post: April 27th 2008, 11:36 AM

/mathhelpforum @mathhelpforum