using a financial calculator, what would be the monthly mortgage payments for each of the following situations?

a. $40,000, 15-year loan at 4.5 percent.

b.$76,000, 30-year loan at 5 percent.

c. $65,000, 20-year loan at 6 percent.

What relationship exists between the length of the loan and the monthly payment? how does the mortgage rate affects monthly payment?