1. Intro to Triangles

2. A B C
All triangles have 3 sides, 3 vertices, and 3 angles Sides: AB, BC, and CA Vertices: A, B, and C Angles: ABC, BCA, and CAB **All angles in a triangle equal 180** Notation: ∆ABC

3. Classifying Triangles

4. Classifying triangles by their ANGLE MEASURES

5. All angles have measures less than 90°.
Acute Triangle
70°
80°
50°
All angles have measures less than 90°.

6. One angle has a measures greater than 90°.
Obtuse Triangle
30°
110°
40°
One angle has a measures greater than 90°.

7. One angle has a measures equal to 90°.
Right Triangle
One angle has a measures equal to 90°.

8. Classifying triangles by their SIDE LENGTHS

9. Two side lengths are the congruent.
Isosceles Triangle 3 7
Two side lengths are the congruent.

10. All side lengths are congruent.
Equilateral Triangle 29
All side lengths are congruent.

11. All side lengths are different.
Scalene Triangle 14 9 5
All side lengths are different.

12. What is this thing called? (by angle measures, then by side lengths)

13. Acute
Scalene
70° 19 16
50°
60° 23

14. Obtuse
Isosceles 13
25°
25° 8
130° 8

15. Right
Scalene 8
90°
66° 11 15
24°

16. Acute
Isosceles 19
73° 12
34°
73° 19

17. Obtuse
Scalene
35° 4x 8x
130°
15° 5x

18. Right
Isosceles
3x° z x
3x°
6x° x