Answer:
Hence new dimension of new garden is 27 by 51
Explanation:
Initial dimension of his square garden = X by X
Final dimension of his rectangular garden = L by B
Perimeter of his garden = 60 = 4X
Hence X = 60/4 = 15 ft
Area of the square garden = 15 x 15 = 225 ft²
New garden dimensions
L + 3 = 2W-----------------Eqn 1
2(L+W) = 60---------------Eqn 2 (since both shapes have the same perimeter)
solving both equations simultaneously
From equation one L = 2W-3, it's now substituted into equation 2
from equation 2, 2L+2W= 60
Hence 2(2W-3) + 2W = 60
W = 27 ft
L= 2(27)-3= 51 ft
Hence length and breadth of new garden is 27 by 51