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Trigonometry - Finding degrees of triangle

  1. May 24, 2007 #1
    I'm having problem with this question:

    From a point A, three straight lines are drawn to points R, S, T so that TRIANGLE ART is right-angled and points R , S, T are collinear. If AR = 12, AS=13, AT=37, determine the area of TRIANGLE AST.

    Is it ok to assume RAS and SAT is 45 degrees?
  2. jcsd
  3. May 24, 2007 #2
    no. your given 2 sides of triangle ARS find the 3rd side. then notice triangle ART. notice what you're given and determine your goal. :smile:
  4. May 24, 2007 #3


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    Homework Helper

    No, of course, you cannot assume things in mathematics. Everything has to be proven.
    Ok AR = 12, AS = 13, and AT = 37, so AR is the smallest of the three.
    So if ART is a right triangle, what should be the right angle, then, is it andle A, R, or T?
    Knowing the right angle, one can use the Pythagorean theorem, ie: a2 + b2 = c2, where c is the length of the hypotenuse in a right triangle.
    You should note that, the area of an triangle ABC can be calculated by:
    A = (1 / 2) AH x BC, there AH is its altitude.
    Can you go from here? :)
  5. May 24, 2007 #4
    Thank you guys so much :)
    That was very helpful
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