Talk:2018 AMC 10A Problems/Problem 21

Hello

I had just a quick question on sol. 3 of this problem. I didn’t get what this part meant “also see that if the parabola goes "in" the circle, then by going out of it (as it will), it will intersect five times. This is impossible. Thus, we only look for cases where the parabola becomes externally tangent to the circle.”

I especially didn’t understand what the author meant in the first sentence “if the parabola goes "in" the circle, then by going out of it (as it will), it will intersect five times.” ? What does “in” the circle mean?

Can someone please clarify this ?

Thanks so much