If the dog chews off 4 inches every day, you first have to multiply the inches by the number of days, which in this case is 3 x 4, which equals 12. In 3 days, he chewed off 12 of the original 15 inches, leaving only 3 inches left.
The question is asking for the area in square feet of a rectangle that is 4 feet long by 3 feet wide. That area is the product of these dimensions: (4 ft)×(3 ft) = 12 ft²
