Explanation

To find the fourth proportional, we need to set up a proportion:

60 : 48 :: 30 : x

Where x is the fourth proportional.

We can rewrite this as: 60/48 = 30/x

Cross-multiplying, we get: 60x = 30 × 48

Simplifying, we get: 60x = 1440

Dividing both sides by 60, we get: x = 24

So, the fourth proportional is 24.