A rectangular cardboard has dimensions as shown. The length of the cardboard can be found by dividing its area by its width. What is the length of the cardboard in inches?

Rectangle with width labeled on the right, width equals 3 1/4 inches. Below the rectangle, it says, length equals? Inside the rectangle, it says, area equals 21 2/3 square inches.

5 1 /12
6 2/3
18 5/12
56 1/3

Please help!!