Blue Rain Co. is going through a growth period and needs to retain earnings to support this growth. Therefore, the company will not pay dividends for the next three years. The company is expected to pay a dividend of $3 per share in four years. It is also expected that the company will maintain a dividend growth rate of 4% per year once it begins paying dividends. If the firms cost of capital is 14%, how much would you be willing to pay for one share of Blue Rains stock?

The formula to solve it is listed as

Share Value of Stock Today = (D4/ ( cost of capital - growth rate) ) / ( + cost of capital) ^ 3

for the root to the power , why is it " ^3 " ? Why to the power of 3 ? where is the value of 3 coming from and what is the criteria value for why it is being selected? Please help.