Let the length of the shortest side be x, then the length of the second side is x + 4 and the length of the third side is 2x - 4.
Then, x + x + 4 + 2x - 4 = 52
4x = 52
x = 52/4 = 13
Therefore, the lengths of the sides of the triangle are: x = 13, x + 4 = 13 + 4 = 17 and 2x - 4 = 2(13) - 4 = 26 - 4 = 22.
i.e. 13, 17, 22