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A triangular support beam of the roof of a large warehouse has a perimeter of 72 meters. The first side is one-third of the second side.
The third side is 19 meters shorter than the second side. What are the lengths of the three sides of the triangular support beam?
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Let x be length of the first side.
Then the length of the second size is 3x,
and the length of the third side is 3x - 19.
The equation for the perimeter is
x + 3x + (3x-19) = 72.
7x = 72 + 19 = 91.
x = = 13.
From this point you can complete the solution on your own.