Algebra-1

To determine which ratio forms a proportion with 3:8, we need to check which of the given ratios is equal to 3:8. We can simplify each option and compare them directly.

Option A, 15:40

Simplify 15:40 by dividing both terms by 5:

15:40 = 3:8

15:40 simplifies to 3:8, so 18:21 is proportional to 3:8.

Option B, 8:3

This is the reverse of 3:8 and cannot be simplified to match 3:8, so it is not proportional to 3:8.