19.6 would be the area of a single base circle πr² is the area formula
Because the number has to have no greater divisors other than one or itself
The answer would be 2 and 4 because if you added these two numbers together it would equal 6 and but if you subtracted 4 from 2 you would get -2. ex- if you have 4 dollars and you gave your friend those 4 dollars but the next day they payed you back 2 they would still need to give you back 2 dollars.