Question

Do the ratios 10:9 and 17:15 form a proportion?

Answer 1

Nope! these ratios do not form a proportion

Explanation:

if you use a calculator to divide 10/9, you get 1.111 repeating.

if you use a calculator to divide 17/15, you get 1.133 repeating.

since 1.111 does not equal 1.113, these ratios are not proportional.