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  • Nov 28, 2010, 12:10 PM
    ray13971
    length of a triangle
    The lengths of the sides of a triangle are consecutive even integers.Find the length of the longest side if it is 14 units shorter than the perimeter
  • Nov 28, 2010, 01:58 PM
    galactus

    Since the sides are consecutive even integers, it has perimeter
    P=x+(x+2)+(x+4)

    If you are familiar with Pythagorean triangles, this alone gives away the solution.

    By Pythagoras:



    Solve for x. You will notice the length of the hypoteneuse is 14 shorter than the perimeter.
    It works out that way.
  • Nov 28, 2010, 09:53 PM
    harum
    Quote:

    Originally Posted by galactus View Post
    If you are familiar with Pythagorean triangles, this alone gives away the solution.

    Looks like we have no reason to assume that the solution is a right angle triangle and ignore that the perimeter is longer than the longest side by a certain number.
    Wouldn't it be just this (here a is the shortest side)?

    a + (a+2) + (a+4) = (a+4) + 14 => a = 6 and so on.
  • Nov 29, 2010, 02:12 AM
    Unknown008

    I was thinking this as well... the triangle is not necessarily a right angled triangle.

    Or, if we want to go faster, we do:

    Let the longest side be x.

    P - 14 = x
    P = (x-4) + (x-2) + x

    [(x-4) + (x-2) + x] - 14 = x
  • Nov 29, 2010, 02:24 PM
    galactus

    Yes, my bad. False assumption.

    Force of habit. I am so used to these problems involving right triangles.

    Coincidentally, I had just gone over a problem that stated "one side of a right triangle is 7 units more than the short side, and the hypoteneuse is 8 more than the short side. What are the side lengths?".

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