Determine if the following are in proportion.
(a) 15, 45, 40, 120
(b) 33, 121, 9,96
(c) 24, 28, 36, 48
(d) 32, 48, 70, 210
(e) 4, 6, 8, 12
(f) 33, 44, 75, 100

Explanation

To determine if the given sets of numbers are in proportion, we need to compare the ratios of the first two numbers with the ratios of the last two numbers in each set. If the two ratios are equal, then the numbers are in proportion.

Let's solve each part step by step:

### (a) 15, 45, 40, 120

1. **Calculate the ratio of the first pair**:
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