5:10, 20:4. 9:10, 45:40. 1:16, 3:18. 1:16, 1:8, 2:18.

Which of these forms a proportion

The pairs of numbers that form a proportion are:

5:10, 9:10
3:18, 1:6

which set

The set that forms a proportion is 5:10, 9:10.

which set forms a proportion:

A. 5:10, 20:40.
B. 9:10, 45:40.
C. 1:16, 3:18.
D: 1:8, 2:18

The set that forms a proportion is B. 9:10, 45:40.