let L be the length
let W be the width
L = 9 + 2W
since the perimeter = 2L + 2W
Perimeter = 2 x (9 + 2W) + 2W
174 m = 18 + 4W + 2W
174 m = 18 + 6W
6W = 174 - 18
6W = 156
W = 156/6
W = 26
L = 9 + 2W
L = 9 + 2 x 26
L = 9 + 52
L = 61
Therefore, length = 61 m and width = 26 m.