The perimeter of a triangle is 59 in. the longest side is 11in. longer than the medium side, and the medium side is 3in longer than the shortest side. find the length of each side of the triangle

We're gonna call x the length of the shortest side.  The medium side is 3 longer than the shorter side, and the longest side is 14 longer than the shortest (11 + 3 = 14):

Perimeter = shortest side + medium side + longest side
59 = (x) + (x + 3) + (x + 14)
59 = 3x + 17
3x = 42
x = 14

Shortest side  =  14
Medium side  =  17
Longest side  =  28