Appalachin mountain goods has paid increasing dividends of $0.12 $0.18 $0.20 a

Appalachin mountain goods has paid increasing dividends of $0.12 $0.18 $0.20 and $0.25 a share over the past four years respectivley. The firm estimates
that future increases in its diviends will be equal to the arithmetic average growth rate over these past four years. The stock is currently selling for $12.60
a share. The risk-free rate is 3.2 percent and the market risk premium is 9.1 percent. What is the cost of equity for this firm if its beta is 1.26?

Please give an explanation with your answer to receive all points. Thank you in advance