A variable rate demand loan showed an initial balance of $11,000.00, payments of $5000.00 after six months, $5000.00 after 21 months, and a final payment after four years. Interest was 9% compounded quarterly for the first 21 months and 8.7% compounded monthly for the remaining time. What was the size of the final payment? The final payment is $ (Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.)