What is the ratio of the third proportional of 5 & 9 and the mean proportional between 1.6 and 8.1?

9:2

Third proportional a, b, c

                            c = \(\frac{b2}{a}\)

third proportional = 5, 9, x

                             x = \(\frac{81}{5}\)

Mean proportional = \(\sqrt {1.6 × 8.1}\)

                           = 3.6

3rd proportional  :     mean proportional

                       \(\frac{81}{5}\) : 3.6

                         9 : 2