Problem 3-13 External Funds Needed The Optical Scam Company has forecast a sales growth of 20 percent for next year. The current financial statements are shown here: a. Using the equation from the chapter, calculate the external financing needed for next year. (Do not round intermediate calculations and round your answer to the nearest whole number, e.g., 32.) Construct the firm's pro forma balance sheet for next year. (Do not round intermediate calculations and round your answers to the nearest whole number, e.g., 32.) o-2. Calculate external financing needed. (Do not round intermediate calculations and round your answer to the nearest whole number, e.g., 32.) E. Calculate the sustainable growth rate for the company based on the current financial statements. (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)