I’m not sure what the rule would be in this context, but those are just the squares of decreasing numbers starting at 10. It’s 10^2, then 9^2, then 8^2, and so on.
First, find the GCF. For these two numbers, it is 36. (Because 36 times 1 is 36 and 36 times 2 is 72) Divide both sides by this, which gives you a 2:1 ratio
