If z varies directly as the square of g and z=45 when g=3 what is g if z=125?

"""z varies directly as the square of g""
z = kg²
""z = 45 when g=3""
45 = k(3²)
Find the value of k.
45 = k(9)
45/9 = k(9)/9
k = 5
""what is g if z=125""
z = kg²
125 = 5g²
125/5 = 5g²/5
25 = g²
√25 = √g²
5 = g

The answer is g = 5."