Tinh has a triangle with side lengths 12 mm, 15 mm, and 18 mm. He wants to reduce the triangle by one-third, so he divides each side length and each angle measure by 3. Which describes Tinh’s reduction? Tinh’s reduction is incorrect; he should have only divided the side lengths by 3. Tinh’s reduction is incorrect; he should have only divided the angle measures by 3. Tinh’s reduction is incorrect; he should have multiplied the side lengths by 3 instead. Tinh’s reduction is incorrect; he should have multiplied the angle measures by 3 instead.