Calculate the "weights" for the long-term financing sources:
Total Stockholder Equity, Long Term Debt, and Preferred Stock (if there is any of this). Do this in two ways:
(a) using the book value of each (look at the Balance Sheet), and
(b) using the market value of the equity (from the question above) and the book values of the Long Term Debt and Preferred Stock (if there is any of this). Optimally, you would use the market value of everything, but I won't make you find all of that.