To solve this, we need to set up a series of conversion ratios.
3.78 ha/x acres = 1 ha/2.4710 acres.
This gives us 3.78(2.4710)/1 = 9.34038 acres. This makes sense because 1 ha is equal to 2.4.
We could have done the conversion all as one multiplication of factors, but it makes sense to break it up into two sets of factors in order to properly explain the process.
Next, we have
9.34038 acres / x ft.^2 = 1 acre / 43,560 ft.^2
So, we have
9.34038(43,560)/1 = 406,866.9528 ft.^2