This document discusses two ways to classify triangles: by their sides and by their angles. Triangles can be classified by their sides as scalene, with no equal sides, or isosceles, with at least two equal sides. They can also be classified by their angles as acute, with all angles less than 90 degrees; right, with one 90 degree angle; or obtuse, with one angle greater than 90 degrees. Examples are given to classify triangles under each system.

1. Classifying Triangles

2. Two Ways to Classify Triangles By Their Sides By Their Angles

3. Classifying Triangles By Their Sides Scalene Isosceles

4. Scalene Triangles No sides are the same length

5. Isosceles Triangles At least two sides are the same length

6. Classifying Triangles By Their Angles Acute Right Obtuse

7. Acute Triangles Acute triangles have three acute angles

8. Right Triangles Right triangles have one right angle

9. Obtuse Triangles Obtuse triangles have one obtuse angle

10. Classify this triangle. Right Scalene

11. Classify this triangle. Obtuse Isosceles

12. Classify this triangle. Acute Scalene

13. Classify this triangle. Acute Isosceles

14. Classify this triangle. Obtuse Scalene

15. Classify this triangle. Right Isosceles