We'd need to figure out the side of the bigger pentagon, which is going to be messy, but we can do it!
The area of a pentagon equation is messy, and we need to solve for the side given the area, which would be sqrt((4*area)/((5(5+2sqrt(5)))^(1/2)) or sqrt((4*8)/((5(5+2sqrt(5)))^(1/2)) . We get this from the pentagon equation, multiplying both sides by 4 dividing (5(5+2sqrt(5)))^(1/2)) from both sides, then square rooting that to get the side length
Plugging it in, we get 2 and some more, and we multiply that by 2 to get the bigger side length. Plugging that into the area equation, we get a=32 and 32-8=24