I am reading this correctly, the width = 1/3 of the length?
If this is the case, and we know that the area is 675, the equation is as follows.
Width x Length = 675 ft2
X = length
1/3 X x X = 675 ft2
To solve for X we have to multiply both sides by 3.
X square 2 = 2601 square feet.
Take the square of each side.
X = 225 sqare feet.
I hope this helps, let me know if you have any questions.