To solve this problem you must apply the proccedure shown below:
1. If the first octagon and the second octagon are similar, you need to find the ratio of the lengths, as below:
[tex] ratio=21.8in/10.9in\\ ratio=2 [/tex]
2. The ratio of the area is:
[tex] ratio=2^{2} =4 [/tex]
4. Then, you must multiply the ratio by the area of the first octagon to calculate the second area:
[tex] A2=4A1\\ A2=4(573.67in)\\ A2=2294.68in^{2} [/tex]
The answer is: [tex] 2294.68in^{2} [/tex]