our consultant firm has been hired by plus premium corp to help them estimate the cost of common equity. the yield on the firm's bonds is 8.71%, and your firm's economists believe that the cost of common equity can be estimated using a risk premium of 2.8% over a firm's own cost of debt. what is an estimate of the firm's cost of common equity from reinvested earnings? (express your answer in % and round to the second decimal place. for example, if your answer is 0.1234, write it as 12.34 and leave out the percentage sign.)