Answer:
True proportion: 12/42 = 10/35.
Step-by-step explanation:
You can do this by performing the division. For example 10/9 = 1.11111.. and 11/10 = 1.1 so they are not proportional.
Or you can factor numerators and denominators and look for common factors.
For example 12/42 = 2 * 6 / 7 * 6 = 2/7
and 10 / 35 = 5*2 / 5*7 = 2/7.
So these 2 are proportional.
