Please explain from where the number 4.96 came and how to solve for it in part b, the answer is already given

Makai Metals Corporation has 8.4 million shares of common stock outstanding and 280,000 6 percent semiannual bonds outstanding, par value $1,000 each. The common stock currently sells for $32 per share and has a beta of 1.2, and the bonds have 20 years to maturity and sell for 113 percent of par. The market risk premium is 7.2 percent, T-bills are yielding 5 percent, and the company's tax rate is 40 percent a. What is the firm's market value capital structure? (Do not round intermediate calculations and round your answers to 4 decimal places, e.g., 32.1616.) Ma = 280,000*1130=316m M. = 8.4m*32=268.8m %d=316/(316+268.8) = 54.04% %e = 1-.5404 = 45.96% b. If the company is evaluating a new investment project that has the same risk as the firm's typical project, what rate should the firm use to discount the project's cash flows? (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) k = 5+1.2 (7.2) =13.64 ka = 4.96 WACC = 13.64*.4596+4.96*.5404+ (1-.4)= 7.8772