Art students have 140 chairs to place in front of an outdoor stage. In what ways can they arrange the chairs

Art students have 140 chairs to place in front of an outdoor stage. In what ways can they arrange the chairs so that there is the same number in each row, at least 6 rows of chairs, and at least 6 chairs in each row?

factors of 140: 1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140
because you need at least 6 chairs in each row and column, you rule out the factors and their respective pairs that are less than 6
7x20
10x14
20x7
14x10

4 ways