We could go into calculating the area of the circle using the information we have, but I think this question just wants us to eyeball it.
Does each quadrant of the circle look like it's taking up more than half, or less than half of each square?
Probably looks like more doesn't it.
Which means that there's at least more than 2 square units being taken up by this square.
It also means that it's taking up less than 4 square units, since each square is not being filled up.
Is it more or less than 3?
It's really depends on the perspective on whoever looks at it, but to me personally, it looks like it's more than 3 units long.
Hope this helps.
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