If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

## 8th grade foundations (Eureka Math/EngageNY)

### Course: 8th grade foundations (Eureka Math/EngageNY)>Unit 2

Lesson 2: Topic B: Foundations

# Classifying triangles

The video explores how triangles are classified based on their sides and angles. It introduces the terms scalene, isosceles, and equilateral for side lengths, and acute, right, and obtuse for angles. It emphasizes that triangles can be categorized in multiple ways based on these characteristics. Created by Sal Khan.

## Want to join the conversation?

• A triangle cannot contain a reflex angle because the sum of all angles in a triangle is equal to 180 degrees. A reflex angle is equal to more than 180 degrees (by definition), so that means the other two angles will have a negative size.
• What if I had a isosceles triangle. Would it be a right angle?
• No, it can't be a right angle because it is not able to make an angle like that. It's no an eqaulateral.
• can i get 10 votes pls and hi im a tringle jk
• To remember the names of the scalene, isosceles, and the equilateral triangles, think like this!
Scalene: I have no rules, I'm a scale! My weight are always different!
Isosceles: I am an I (eye) sosceles (Isosceles)
Equilateral: I'm always equal, I'm always fair!
• Good Quote
• Why is an equilateral triangle part of an icoseles triangle.
• I've asked a question similar to that.
An equilateral triangle has all three sides equal, right?
But on the other hand, we have an isosceles triangle, and the requirements for that is to have ONLY two sides of equal length. That's why.
• Are all triangles 180 degrees, if they are acute or obtuse?
• Yes. All of the internal angles of a triangle equal 180 degrees.
• hello pickels :)
• a pickle is not in the video
(1 vote)
• An equilateral triangle has all three sides equal?
But on the other hand, we have an isosceles triangle, and the requirements for that is to have ONLY two sides of equal length.
• An equilateral triangle has all three sides equal?
But on the other hand, we have an isosceles triangle, and the requirements for that is to have ONLY two sides of equal length.
Answer: Yes, the requirement for an isosceles triangle is to only have TWO sides that are equal. (e.g, there is a triangle, two sides are 3cm, and one is 2cm. That is an isosceles triangle. An equilateral triangle would have all equal sides.).
• Good question! A reflex angle is an angle measuring more than 180 degrees but less than 360 degrees.

Have a blessed, wonderful day!