Find the arc measure

To prove that def ~ gfh by the sss similarity theorem using the information provided in the diagram, it would be enough additional information to know that

Find the roots of the equation below. x^2 - 6 + 9 = 0

Let f(x) = x+3 and g(x) = 1/x the graph of (fog)(x) is shown below what is the range of (fog)(x)?