1. Triangle Classification

2. Objectives Classify triangles by their angle and side measures Find the sum of the measure of the interior and exterior angles of a triangle

3. Not EQUILATERAL EQUILATERAL So What is an Equilateral? Three equal sides

4. Not Isosceles! Isosceles Isosceles ! So What is an Isosceles? Two or more congruent (equal) sides

5. Not SCALENE SCALENE What is a SCALENE? No equal sides

6. Triangle classification based on length of sides Equilateral Triangle Three equal sides Isosceles Triangle Two or more congruent (equal) sides Scalene Triangle No equal sides

8. ACUTE SO WHAT IS AN “ACUTE” TRIANGLE? Each angle is acute / all angles measure less than 90°

10. Not OBTUSE OBTUSE What is an OBTUSE Triangle? One angle is obtuse. It has an angle greater than 90°

11. Not RIGHT RIGHT So what is a RIGHT triangle? One angle is a right angle. One angle is exactly 90°

13. Triangle classification based on angles Acute Triangle Each angle is acute. All angles less than 90° Obtuse Triangle One angle is obtuse. It has an angle greater than 90° Right Triangle One angle is a right angle. One angle is exactly 90°

14. Triangle classification based on angles (continuation) Equiangular (also equilateral) All angles are the same. Always is an equilateral triangle

15. What type of triangle is this? By length: A. Equilateral B. Isosceles C. Scalene By angle: D. Acute E. Obtuse F. Right G. Equiangular

16. What type of triangle is this? By length: A. Equilateral B. Isosceles C. Scalene By angle: D. Acute E. Obtuse F. Right G. Equiangular

17. It’s OK Bob. She wasn’t acute one.

18. What type of triangle is this? By length: A. Equilateral B. Isosceles C. Scalene By angle: D. Acute E. Obtuse F. Right Equiangular

19. What type of triangle is this? By length: A. Equilateral B. Isosceles C. Scalene By angle: D. Acute E. Obtuse F. Right G. Equiangular