1. Bell Work Note: The figures are not drawn to scale.
Order the side lengths from least to greatest.
Order the angle measurements from least to greatest. B A B C
7 in.
10 in.
9 in.
62°
65°
53° A C
AB, AC, and BC
<B, <A, <C

2. Finding an Angle Measure in a Triangle
Find the value of x in the triangle shown.
We know that:
x + 83 + 26 = 180
x + 109 = 180
-109 
x = 71
So, the value of x is 71°.
26
83 x

3. You Try Find the value of x in the triangle shown. We know that:
x = 62
So, the value of x is 71.
26
92 x

4. Note: The figures are not drawn to scale.
You try!
Note: The figures are not drawn to scale. A B C
27°
3x°
78°
Find the value of x. B
82°
67° x°
3x + 27°+ 78°= 180°
3x = 180
3x = 75°
x = 25° A C
x + 82°+ 67°= 180°
x = 180
x = 31°

5. Classifying Triangles by sides and angles
Beat the Computer Drill

6. Review!

7. REMEMBER: YOU HAVE TO BEAT THE CLOCK! You only have 10 seconds!
Directions:
Classify each triangle by both its SIDES and its ANGLES. You will have 10 seconds before the computer shows you the answer.
When the slide appears, as a group choose BOTH NAMES for the type of triangle and hold up your answer.
REMEMBER: YOU HAVE TO BEAT THE CLOCK! You only have 10 seconds!

8. Trial Run
Classify by sides:
Classify by angles:

9. also also Isosceles Equilangular Triangle Triangle Classify by sides:
Classify by angles:
Equilateral
Triangle
Acute
Triangle
also
Isosceles
Triangle
also
Equilangular
Triangle

10. Classify by sides:
Classify by angles:

11. Classify by sides:
Classify by angles:
Isosceles
Triangle
Obtuse
Triangle

12. Classify by sides:
Classify by angles:

13. Classify by sides:
Classify by angles:
Isosceles
Triangle
Acute
Triangle

14. Classify by sides:
Classify by angles:

15. Classify by sides:
Classify by angles:
Scalene
Triangle
Obtuse
Triangle

16. Classify by sides:
Classify by angles:

17. Classify by sides:
Classify by angles:
Scalene
Triangle
Right
Triangle

18. Classify by sides:
Classify by angles:

19. Classify by sides:
Classify by angles:
Isosceles
Triangle
Right
Triangle

20. Classify by sides:
Classify by angles:

21. Classify by sides:
Classify by angles:
Scalene
Triangle
Acute
Triangle

22. Classify by sides:
Classify by angles:

23. Classify by sides:
Classify by angles:
Isosceles
Triangle
Obtuse
Triangle

24. Classify by sides:
Classify by angles:

25. Classify by sides:
Classify by angles:
Scalene
Triangle
Obtuse
Triangle

26. Classify by sides:
Classify by angles:

27. Classify by sides:
Classify by angles:
Scalene
Triangle
Acute
Triangle

28. Classify by sides:
Classify by angles:

29. Classify by sides:
Classify by angles:
Isosceles
Triangle
Right
Triangle

30. Classify by sides:
Classify by angles:

31. Classify by sides:
Classify by angles:
Isosceles
Triangle
Acute
Triangle

32. Classify by sides:
Classify by angles:

33. Classify by sides:
Classify by angles:
Scalene
Triangle
Right
Triangle

34. Classify by sides:
Classify by angles:

35. also also Isosceles Equilangular Triangle Triangle Classify by sides:
Classify by angles:
Equilateral
Triangle
Acute
Triangle
also
Isosceles
Triangle
also
Equilangular
Triangle

36. Are you a triangle expert?

37. Review
In order to form a triangle, the sum of the angles has to equal 180°.
In order to form a triangle, the sum of the two smallest side lengths has to be GREATER than the third side.
In a triangle, the largest angle is opposite the longest side. The smallest angle is opposite the shortest side.
Skills Check will be on Thursday!!!

38. Practice