Fixeter Corp has a market value balance sheet comprised of $$750,000,000$ in debt and $$250,000,000$ in equity. The firm can borrow at a rate of $6\%$ per annum and is subject to a $30\%$ tax rate. If the unlevered cost of equity for the firm is $10\%,$ then a$.$ Calculate the current levered cost of equity for the firm.

b$.$ What is the firm$$s weighted average cost of capital $($WACC$)?$