Please, can you make the formula?

Ezzell Corporation issued preferred shares with a declared dividend of 10% at par. These types of securities today produce 8% and their par value is $ 100. Assume that dividends are paid annually. to. How much are the company's preferred shares worth? b. Suppose the level of interest rates reaches a point where they yield 12% at the present time. How much will your preferred shares be worth?efined