Math Angles

1. What is an Angle?

2. when two straight lines or rays meet at a
common endpoint.

3. • When two straight lines or rays
meet at a common endpoint.
• The common point of contact
is called the vertex of an angle

4. Symbol of Angle
• ∠ represents an angle.
• Angles are measured in
degrees (°) using a
protractor.

8. Goal
How to estimate and compare acute, obtuse
and reflex angles?
Online protractor & angle maker | interactive
angle visualiser | visnos
Online Protractor | Angle Measuring Tool
(ginifab.com)

12. Go around your class and find real examples of angles. You
can also make angles by moving things. Find 4-5 examples of
each type of angle. If you can try to draw picture or use
words to describe the angle!

13. Student Template

14. Right Angle
A right angle is 90⁰.

15. Acute Angle
An acute angle is less than 90⁰.

16. Obtuse Angle
An obtuse angle is more than 90⁰ and less than 180⁰.

17. Straight Angle
A straight angle is exactly 180⁰.

19. Reflex Angle
A reflex angle is greater than 180⁰ and less than 360⁰.

20. What kind of angle is this?
Obtuse Straight Reflex
Right Acute

21. What kind of angle is this?
Obtuse Straight Reflex
Acute
Right

22. What kind of angle is this?
Straight Reflex
Acute
Right Obtuse

23. What kind of angle is this?
Reflex
Acute
Right Obtuse Straight

24. What kind of angle is this?
Acute
Right Obtuse Straight Reflex

26. How 4 right angles make 360⁰?
GOAL

27. What Type of Angle?
Is the angle shown acute, obtuse or reflex?
Obtuse Reflex
Acute

28. What Type of Angle?
Is the angle shown acute, obtuse or reflex?
Obtuse Reflex
Acute

29. What Type of Angle?
Is the angle shown acute, obtuse or reflex?
Obtuse Reflex
Acute

30. What Type of Angle?
Is the angle shown acute, obtuse or reflex?
Obtuse Reflex
Acute

31. What Type of Angle?
Is the angle shown acute, obtuse or reflex?
Obtuse Reflex
Acute

32. 360° Angles
180
A complete turn will always
measure 360°.
There are four 90° right angles
in a whole turn.
90
90
90
90
1 right angle = 90
2 right angles = 180
3 right angles = 270
4 right angles = 360
45
45
45
45
½ a right angle = 45°
We can use these known facts to
help us calculate missing angles
of a full turn.

33. TO FIND THE MISSING
ANGLE
LESSON
OBJECTIVES

35. Horizontal line
a
b
Angles a + b = 180o
70o
b
Angle b = 180 – 70 = 110o
x
35o
Angle x = 180 – 35 = 145o
90 90
Angles on a straight line add to 180o
180o
Angles on a Line

37. 90
90
90
90
Vertical
Horizontal
360o
1
360o
2
360o
3
360o
4
360o
Angles at a Point

38. a
b
c
d
Angles at a point add to 360o
Angle a + b + c + d = 3600
Angles at a Point

39. Introduction
Circle 5 pairs of numbers that total 180.
125 55 62 110
95 100 80 70
60 90 67 123
90 40 143 37

40. Introduction
Circle 5 pairs of numbers that total 180.
125 55 62 110
95 100 80 70
60 90 67 123
90 40 143 37

41. Varied Fluency 1
Match the facts.
Degrees on 2
straight lines
270
Degrees in 3
right angles
180
Degrees in 2
right angles
360

42. Varied Fluency 1
Match the facts.
Degrees on 2
straight lines
270
Degrees in 3
right angles
180
Degrees in 2
right angles
360

43. CALCULATE MISSING ANGLES ON A STRAIGHT LINE
LESSON OBJECTIVE

44. Varied Fluency 3
Calculate the missing angle.
77
o
x
Angles not drawn to scale.

45. Varied Fluency 3
Calculate the missing angle.
180
o
– 77
o
= 103
o
77
o
Angles not drawn to scale.
103
o

47. Goal-
•Identify point,
lines, segments and
rays

52. https://www.google.com/maps/place/GEMS+Modern+Academy/@10.0022286,76.3681
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