What is the difference in the mean proportional between 1.8 and 3.2 and the third proportional to 5 and 3?

0.6

Formula for mean proportion of A, B = $\sqrt{A\;\times\;B}$

Mean proportion of 1.8 and 3.2 = \(\sqrt {1.8\; \times\; 3.2}\)

                                                 = 2.4

Formula for third proportion of A, B = $\frac{B\;\times\;B}{A}$

Third proportion of 5 and 3 =  \(\frac{3\; \times\; 3}{5}\)     

                                           = \(\frac{9}{5}\) = 1.8

Difference between them = 2.8 - 1.8 = 0.6