An angle is formed by two lines or rays diverging from a common point called the vertex. There are several types of angles including acute, right, obtuse, straight, and reflex angles defined by their degree measurements. The parts of an angle include the vertex, two arms, and degrees. Angles can be named using the less than symbol followed by three letters to indicate the vertex points.

1. angles

2. What is an angle
 A shape, formed by two lines
or rays diverging from a
common point (the vertex).

3. Types of angles

4. Acute angle
 An angle that measures less
than ninety degrees but more
than zero degrees

5. Right angle
 An angle of 90°, as in a corner
of a square, or formed by
dividing a circle into quarters.

6. Obtuse angle
 An angle that measures more
than 90 degrees but less than
180 degrees

7. Straight angle
 Two lines that form a right
angle are said to be normal,
orthogonal, or perpendicular.
Angles larger than a right
angle and smaller than a
straight angle (between 90°
and 180°) are called obtuse
angles ("obtuse" meaning
"blunt").

8. Reflex angle
 The reflex angle is the
larger angle. It is more than
180° but less than 360° If you
choose the smaller angle you
might have an Acute Angle, or
an Obtuse Angle instead: The
larger angle is a Reflex Angle,
but the smaller angle is an
Acute Angle.

9. Full angle
 A full angle, also called a
perigon, is an angle equal to
radians corresponding to the
central angle of an entire
circle. Four right angles or
two straight angles equal one
full angle

10. Parts of an angle

11. Vertex
The column point where
two rays meet.

12. Arms
The rays that make angle.

13. Degrees
 The measure of the size of an
angles.

14. Naming angles

15. Naming angles
 One way is to use the < symbol followed by three letters.

16. Naming angles example
 = <ABC or <CBA

17. Quiz time

18. Which angle is equal to exactly 90 degrees
a) Right angle
b) Acute angle
c) Obtuse angle
d) Reflex angle

19. Answer: A

20. Which angle is less than 360 but greater than
180
a. Obtuse angle
b. Full rotation
c. Reflex angle
d. Straight angle

21. Answer: C

22. How many arms an angle has
a. One
b. Two
c. Three
d. Four

23. Answer: B

24. How many vertex do an angle has
a) One
b) Two
c) Three
d) four

25. Answer: A