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.

Step-by-step explanation:

The side lengths if given triangle are 12 mm, 15 mm, and 18 mm.

If we reduced or enlarge a figure, then the corresponding sides of preimage and image are proportional and corresponding  angles are congruent.

Tinh wants to reduce the triangle by one-third. It means, each side of image is one-third of its corresponding side.

He divides each side length and each angle measure by 3. He is incorrect because the angles remains same.

Therefore, Tinh’s reduction is incorrect; he should have only divided the side lengths by 3.

ab will be equal to