Given that A town with a population of 3,445 doubles in size every 89 years.
After 89 years, the population is

After the second 89 years, the population is

Here we get the exponent of 2 is equal to the times of 89 years.
In general. after n times of 89 years, the population is

We need to find how many times 89 in 356.
The number of 89 in 356 is

The number of population after 365 years is

Hence the population will be 55120 after 356 years from now.