The sum of the fourth proportional of 4, 5, 16 and the mean proportional of 4, 16, is

25 28 30 32

28

The fourth proportional of 4, 5, 16 = \(\frac{16 × 5}{4}\) = 20 The mean proportion of 4, 16 = \(\sqrt {16 × 4}\) = 8 So, the sum of the fourth proportion and mean proportion = 20 + 8 = 28