Since the center is considered the corner that they both share, here are the answers figure a goes with the first, figure b goes with the last, figure c goes with the second, and figure d goes with the third. Hope this helps.
<span>So we need to explain how we know 21/30 is greater than 2/3. Well lets expand 2/3 by multiplying the numerator and the denumerator by 10. That way we get 20 / 30. Since 21/30 has 1/30 more than 20/30 we can clearly see that 21/30 is greater than 20/30 or 2/3.</span>