By using what we know about octagons, we will see that:
For an octagon of side length S, the area is:
A = 2*(1 + √2)*S^2
In this case, the area of the smaller octagon is:
19.28 in^2 = 2*(1 + √2)*S^2
Solving for S we get:
S = √( 19.28 in^2/(2*(1 + √2))) = 2.03 in
If we apply an enlargement of a factor 3.5, the new side length is:
S' = 3.5*2.03 in = 7.11 in
Then the area of the larger octagon is:
A' = 2*(1 + √2)*(7.11 in)^2 = 244.89 in^2
b) For an octagon of side length S, the radius is:
R = S*√(1 + 1/√2)
Then the radius of the larger octagon is:
R' = (7.11 in)*√(1 + 1/√2) = 9.29 in
Then the diameter of the box must be:
D = 2*R' = 2*9.29 in = 18.58 in
If you want to learn more about octagons, you can read:
https://brainly.com/question/1592456