What is the ratio of the fourth proportional to 4, 7 and 20 to the mean proportional between 7 and 28?

Explanation

1. 01

   Fourth proportional to 4, 7, 20: $\frac{7 \times 20}{4} = 35$.

2. 02

   Mean proportional between 7 and 28: $\sqrt{7 \times 28} = \sqrt{196} = 14$.

3. 03

   Required ratio = $35 : 14 = 5 : 2$.