Answer: The width of the border is 4 inches
Step-by-step explanation: The paper frame has its dimensions given as 20 inch by 24 inch. That means the area of the paper frame would be;
Area = L x W
Area = 20 x 24
Area = 480 square inches.
However, the photo itself covers an area of 320 square inches of this total surface area. If the photo has a uniform border, that means the photo and the paper frame are best described as congruent parallelograms (similar rectangles).
The ratio of the area of both paper frame and photo is given as;
Ratio = 480 : 320
Ratio = 3 : 2
When the length of the photo frame is given as 24, the length of the photo would be
3/2 = 24/L
L = (2 x 24)/3
L = 48/3
L = 16
Having calculated one side of the photo as 16 inches and the area has been given as 320 square inches, the other side of the photo is now derived as;
Area = L x W
320 = 16 x W
320/16 = W
20 = W
The dimensions of the paper frame is given as 24 inches and 20 inches, while those of the photo is given as 20 inches by 16 inches. The difference in both dimensions is 4 inches on either side (24 - 20 = 4, and 20 - 16 = 4)
Therefore the width of the border is 4 inches