A demand loan of $8000.00 is repaid by payments of $4000.00 after two years, $4000.00 after four years, and a final payment after seven years. Interest is 9% compounded monthly for the first two years, 10% compounded quarterly for the next two years, and 10% compounded semi-annually thereafter. What is 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.)