3/4 of a pizza is always the same as 6/8 of a pizza. While 3/4 and 6/8 are equivalent fractions, 3/4 and 6/8 of a pizza could represent different amounts.

Who is correct

3/4 of a pizza is always the same as 6/8 of a pizza

as a counterexample you could draw 2 circles and divide one by 4 and the other by 8. then shade 3 of the circle divided by 4 and shade 6 of the circle divided by 8

hope this is what your looking for

3/4th and 6/8ths of a pizza are always the same because you are not losing mass of the pizza by cutting it into smaller or larger pieces.