Since there are two unknowns (length and width), set up two equations.
L = W + 2
P = 2L + 2W
52 = 2(W + 2) + 2W
52 = 2W + 4 + 2W
52 = 4W + 4
48 = 4W
W = 12
L = 12 + 2 = 14
2(14) + 2(12) = 52
So the length is 14 m and the width is 12 m.