Because the fencing material will be placed after the first pen and before the 10th pen, the fencing material that the kennel owner have will have to be divided only by 9. This give us an answer of 30 ft.
The calculated 30 ft above is equal to the width of the pen. The width is calculated by dividing the area by the length. This gives us, width = 100 ft² / 30 ft width = 3.33 ft The dimension of the rectangle is therefore, 33.3 ft width and the length of 30 ft.