The polygons are regular polygons. Find the area of the shaded region to the nearest tenth

(An image bellow of a white box inside a shaded box. The white box has a line from the center to the corner labeled 4cm. The shaded box has the same thing but it's 9cm)

This has confused me a lot and I keep getting different answers. I would appreciate some help.

8 answers

www.onlinemathlearning.com/area-shaded-region.html

^Copy-paste that link into your search bar and you'll be able to learn how to figure out the answer.

Good luck!
I appreciate the help, but my problem here didn't actually give me any sides to figure out how I was going to find the area ;-; Thanks for trying to help though!
in the white box, half the diagonal is 4. If the box is a square, then the area is 1/2 d^2 = 1/2 * 8^2 = 32
Similarly, the large box has area 1/2 * 18^2 = 162
So I guess the shaded area is 162-32 = 130
Oh! Okay. Thanks oobleck!
The answers for the quick check are:
1. A) 688.2 ft^2
2. B) 229.1 m^2
3. B) 8.6 ft^2
4. C) 566.9 in^2
5. B) 635.1 m^2
6. 130 or 130.0 (both are acceptable)

and for the practice:
1. D) 173.8 cm^2
2. A) 7554 m^2
3. A) 311.3 km^2
4. C) The area of Pentagon A is equal to 1.53 times the area of Pentagon B
5. D) 48.2 cm^2
6. C) 237.8 in^2
7. C) 20.8 m^2
8. A) 29.7 cm^2
9. D) $51.96
10. C) 24 in^2
... is right, i got 100%
TYSM "..."
… is still correct in 2023 tysm