Answer:
All four interior edges are 4 inches, 3 inches, 4 inches and 3 inches.
Explanation:
Givens
- The area of the frame is 18 square inches.
- The wide of the frame is 1 inch.
- One of the outer edges of the fram is 5 inches long.
If one side is 5 inches long and the wide is 1 inch, then the inner side is 3 inches long, becase we must subtract the 2 inches of the wide.
The image attached shows all relations we need to make regarding both areas.
The inner area is defined as

The area of the whole

The area of the frame is defined as the difference of the inner area and the whole area

Now, we solve for


The interior each is defined as b-2, so its length is

Therefore, the interior edges are 4 inches and 3 inches long.
All four interior edges are 4 inches, 3 inches, 4 inches and 3 inches.