Acme Storage has a market capitalization of $$189$ million and debt outstanding of $$240$ million. Acme plans to maintain this same$$ debt$-$equity ratio in the future. The firm pays an interest of $8\mathrm{.}7\%$ on its debt and has a corporate tax rate of $20\%.$a$.$ If$$ Acme's free cash flow is expected to be $$21\mathrm{.}45$ million next year and is expected to grow at a rate of $6\%$ per$$ year, what is$$ Acme's WACC?b$.$ What is the value of$$ Acme's interest tax$$ shield?$$