A firm has $7.7 Billion debt outstanding, with a yield to maturity of 4.2% and a coupon rate of 5.4%. They have 144 million preferred shares outstanding, currently trading at $84.57. They also have 787 million common shares outstanding, currently trading at $47.97 and the corporate tax rate is 22%. If the return on common stock (return on equity) is 8.1% and the return on preferred stock is 7.4% what is the Weighted Average Cost of Capital (WACC)?