{(2, 3), (1, 5), (2, 7)} - NOT because 2->3 and 2->7 {(11, 9), (11, 5), (9, 3)} - NOT because 11->9 and 11->5 {(3, 8), (0, 8), (3, -2)}
- NOT because 3->8 and 3->-2
<em>In problems involving proportions, we can use cross products to test whether two ratios are equal and form a proportion. To find the cross products of a proportion, we multiply the outer terms, called the extremes, and the middle terms, called the means.</em>
