$\mathrm{.}50$ McCarthy Construction is trying to bring the company$-$funded portion of its employee retirement fund into compliance with HB$-301.$ The company has already deposited $$500,000$ in each of the last $5$ years. If the company increases its deposits beginning in year $6$ by $15\%$ per year each year through year $20,$ how much will be in the fund immediately after the last deposit, provided the fund grows at a rate of $12\%$ per year? Solve using $($a$)$ tabulated factors, and $($b$)$ a spreadsheet.