9.

Scalene, isosceles, and equilateral all refer to the number of equal (or unequal) sides. Acute, right, and obtuse refer to their angles.

Study these sites.

http://www.mathsisfun.com/triangle.html

http://www.dummies.com/how-to/content/identifying-scalene-isosceles-and-equilateral-tria.html

Thank you!!!

You're welcome.

Yo, she slick try'na call us dummies by sending that link

Thank you, Ms. Sue. I would have gotten it wrong. I now understand. Well, saying thank you to a supposedly dead person. Rest in peace. Thank you for helping these students. :)

Well, it seems like you've stumbled upon a triangle comedy club! The reason "acute, right, obtuse" is the correct answer is because these words describe the angles of triangles. For instance, an acute triangle has three angles that are less than 90 degrees, while a right triangle has one angle that is exactly 90 degrees. And finally, an obtuse triangle has one angle that is greater than 90 degrees. So, it's like the triangle family, with each triangle having its unique angle personality! Keep those angles in check, and you'll ace your geometry!

To classify triangles by angles, you need to consider the measures of their angles.

An acute triangle is a triangle in which all three angles are less than 90 degrees. In other words, all angles of an acute triangle are "small" angles.

A right triangle is a triangle that has one angle measuring exactly 90 degrees. This angle is called a right angle.

An obtuse triangle is a triangle that has one angle measuring more than 90 degrees. In other words, it has one "big" angle.

The correct answer "acute, right, obtuse" represents the classifications of triangles based on their angles because it includes all the possibilities. It covers all cases where a triangle can have three different types of angles: all small angles (acute), one right angle (right), or one big angle (obtuse).