1. 10-5 Triangles
Math Notes
Measurement & Geometry 2.0

2. 3 Triangles Based on ANGLES
45˚
90˚ 45˚

3. 3 Triangles Based on ANGLES
45˚
90˚ 45˚
RIGHT
Triangle
One angle
is 90˚ (right
angle)

4. 3 Triangles Based on ANGLES
45˚
80˚
90˚ 45˚
40˚ 60˚
RIGHT
Triangle
One angle
is 90˚ (right
angle)

5. 3 Triangles Based on ANGLES
45˚
80˚
90˚ 45˚
40˚ 60˚
RIGHT ACUTE
Triangle Triangle
One angle All three
is 90˚ (right angles are
acute
angle)

6. 3 Triangles Based on ANGLES
45˚
80˚ 50˚
90˚ 45˚ 100˚
40˚ 60˚
30˚
RIGHT ACUTE
Triangle Triangle
One angle All three
is 90˚ (right angles are
acute
angle)

7. 3 Triangles Based on ANGLES
45˚
80˚ 50˚
90˚ 45˚ 100˚
40˚ 60˚
30˚
RIGHT ACUTE
Triangle OBTUSE
Triangle
Triangle
One angle All three
One angle
is 90˚ (right angles are
is obtuse
acute
angle)

9. 45˚
90˚ 45˚
45˚
90˚
+ 45˚

10. 45˚
80˚
90˚ 45˚
60˚
40˚
45˚ 80˚
90˚ 40˚
+ 45˚ + 60˚

12. 100˚
50˚ 50˚
+ 30˚
100˚
30˚

13. 100˚
50˚ 50˚
+ 30˚
100˚
30˚
The sum of the angles of ANY triangle is ALWAYS...

14. 100˚
50˚ 50˚
+ 30˚
100˚
30˚
The sum of the angles of ANY triangle is ALWAYS...
180˚

15. 3 Triangles Based on SIDES

16. 3 Triangles Based on SIDES
5” 5”
5”

17. 3 Triangles Based on SIDES
5” 5”
5”
EQUILATERAL
TRIANGLE
ALL sides are
the same length

18. 3 Triangles Based on SIDES
5” 5” 6” 6”
5” 3”
EQUILATERAL
TRIANGLE
ALL sides are
the same length

19. 3 Triangles Based on SIDES
5” 5” 6” 6”
5” 3”
EQUILATERAL ISOSCELES
TRIANGLE TRIANGLE
ALL sides are TWO sides are
the same length the same length

20. 3 Triangles Based on SIDES
5” 5” 6” 6” 6” 4”
5” 3” 5”
EQUILATERAL ISOSCELES
TRIANGLE TRIANGLE
ALL sides are TWO sides are
the same length the same length

21. 3 Triangles Based on SIDES
5” 5” 6” 6” 6” 4”
5” 3” 5”
EQUILATERAL ISOSCELES SCALENE
TRIANGLE TRIANGLE TRIANGLE
ALL sides are TWO sides are NO sides are
the same length the same length the same length

22. Notation for Triangles

23. Notation for Triangles
B
A C

24. Notation for Triangles
B
Write this down as:
A C

25. Notation for Triangles
B
Write this down as:
ABC
A C

26. Notation for Triangles
B
Write this down as:
ABC
You say:
“triangle ABC”
A C

27. Notation for Triangles

28. Notation for Triangles
Y
X Z

29. Notation for Triangles
Y
Write this down as:
X Z

30. Notation for Triangles
Y
Write this down as:
___
X Z

31. Notation for Triangles
Y
Write this down as:
___
You say:
“triangle ____”
X Z