One side of a triangle is one-third the longest side. The third side is 13 feet less than the longest side. The perimeter is 85. Find all three sides.
x + x-13 + 1/3 x = 85
7/3 x = 98
1/3x = 14
x = 42
x-13 = 29
1/3 x = 14
(42,29,14)
+876 
