Engineering Economics.Look at the file for diagram

Suppose you make monthly payments of $1,200 into a savings account for 4 years as shown below. The money in the account will be used to fund a decreasing annual uniform-gradient series that begins at the end of the 7th year and ends at the end of the 16th year. What is the value of the gradient (G) that makes the gradient series equivalent to the uniform flow of payments of $1,200 per month for 4 years? Assume a nominal interest rate of 12% compounded monthly. Your calculations must include the use of a gradient factor. Show all applicable equations and all calculations.