Exact formula is: Initial Size x ( 1 + growth rate)^n where n is the number of periods.

In this case $520m x ( 1+ 0.047)^3 where 3 is the number of years, 520m is the initial market size, and 0.047 is the growth rate.

Since this exact calculation is hard to do without a calculator, you round the 4.7% (or 0.047) to 5.0% (or 0.05), and adjust the formula to the following: $520m ( 1 + 0.05 x 3), or $520 x 1.15, which comes out to $598m. This is just the standard way of making the formula manageable without a calculator, but beware that the more periods you are using this estimate over, the more your answer will be __underestimated.__

Note that if the market was shrinking instead of growing, you'd just make the growth rate negative.

Hope this helps!