What is the rate of interest on a 1 year loan starting 3 years from now, implied by the following term structure: (i) A 1-year zero coupon bond has a yield to maturity of 1%; (ii) A 2-year zero coupon bond has a yield to maturity of 2%; (iii) A 3 year zero coupon bond has a yield to maturity of 3%, and (iv) A 4-year zero coupon bond has a yield to maturity of 4%. (In other words, show your calculation of the forward 1-year interest rate starting 3 years from now.)

Please provide explanation and answers!