I believe the next one would be 13.2 because if you add 8.4 to -6.4 it gets 4.8 so you just do the same thing
Here we apply the Pythagorean theorem:
c^2=a^2+b^2
The diagonal of the opening will be:
c^2=3^2+3^2
c^2=9+9
c^2=18
c=3√2 ft
The diagonal of the wood will be:
c^2=4^2+8^2
c^2=16+64
c^2=80
c=4√5 ft
The space will not be enough for the plywood to pass
