For two ratios to form a proportion they have to be equal.
To see if two ratios are equal we express them in their simplest form.
In this case we notice that in the first ratio both numbers are multiples of five, then:

In the second case we notice that both numbers are multiples of 2, then:

Since both ratios can be simplified to the same final ratio, they form a proportion.
16 skateboards,because 8 is smaller than 12.Also 8 is smaller than 16.But 16 is greater than 12 and 8.
Answer:
a common factor would be 5m^4n^3 or 15m^2n^2
Step-by-step explanation:
not sure what terms they want you to choose from but anything that starts with a number (5,10,15,) and "m" would any number 5 would go into