Results 1 to 2 of 2

Math Help - Trig word problem

  1. #1
    Newbie
    Joined
    Nov 2008
    Posts
    16

    Trig word problem

    The bases of a trapezoid are 400 cm and 225 cm respectively, the angles that the sides make with the longer base are 68 degrees 40 minutes and 72 degrees 10 minutes. Find the sides of the trapezoid.

    -------
    I don't get it. This seems an isosceles trapezoid. Therefore, the base angles must be equal. But the given says it's not. Help please..
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Nov 2008
    From
    France
    Posts
    1,458
    Hi

    Have a look to the sketch below
    L = 400 cm
    l = 225 cm
    \alpha = 68\,deg\,40'
    \beta = 72\,deg\,10'
    a and b are the unknown sizes
    They are linked by the following equations

    a \sin \alpha = h = b \sin \beta
    a \cos \alpha + l + b \cos \beta = L

    This is s linear system

    a = \frac{\sin \beta}{\sin(\alpha + \beta)} (L-l)

    b = \frac{\sin \alpha}{\sin(\alpha + \beta)} (L-l)

    a = 263.77 \,cm
    b = 258.10 \,cm

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Trig Word Problem
    Posted in the Trigonometry Forum
    Replies: 7
    Last Post: November 20th 2011, 12:57 PM
  2. Trig word problem - solving a trig equation.
    Posted in the Trigonometry Forum
    Replies: 6
    Last Post: March 14th 2011, 08:07 AM
  3. Replies: 3
    Last Post: January 2nd 2011, 09:20 PM
  4. Word Problem - Trig
    Posted in the Trigonometry Forum
    Replies: 7
    Last Post: June 19th 2009, 01:33 PM
  5. trig word problem
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: September 26th 2008, 03:04 PM

Search Tags


/mathhelpforum @mathhelpforum