x - the shortest side
2x
x + 28
The sum of these must be equal to the perimeter of the flower bed, so
x + 2x + x + 28 = 184
4 x + 28 = 184 Combined like terms
4x = 156 Subtracted 28 from both sides
x = 39 Divided both sides by 4.
So the dimensions are 39 feet, 78 feet, and 67 feet