The document defines different types of angles and how to measure them using a protractor. It explains that angles can be measured in degrees from 0° to 360° and defines right angles as being 90°, acute angles as less than 90°, and obtuse angles as greater than 90° but less than 180°. A straight angle is 180°. Examples are given measuring various angles and identifying their type.

2.  To be able to analyze and measure angles
using a protractor .
 To be able to identify angles as right
angle, acute angle, obtuse angle, straight angle.
 To be able to learn what is angle is.

3. Angles can be measured in degrees or
radians. For the time being, we will strictly
talk about angles in terms of their degree
measure. The symbol for degrees is °.
Angles can measure from 0°up to 360°.
Angles with no measure are called zero
angles, while angles of 360° are full
rotations.

4. A
An angles is a figure formed
by two rays with common
endpoint , and which are
not on the same line. Two 1
B
rays are called the sides of O
the angle. The common
endpoint of the sides of an
angles is called the vertex.
•In the figure above , rays OA and OB are the two sides of the angle.
Point O is the vertex of the angle.

5. The measures of an angle refers to the opening made from one side of
the angle to the other. An arrow from one side of the angle to the other
usually denotes the particular measured desired.
B
40
C

6. B
40
A
C
To use the protractor, place the center point of the protractor on the
vertex of the angle to be measured. Line up the marked label 0 on
either scale with one side of the angle . In the figure above, the measure
of angle BAC is 40 degrees.

7. •A right angle is an angle
whose measure is exactly 90°
J
90
K
L

8. •An acute angle is an angle
whose measure is less than
90°
A B
E F
C
D

9. •Obtuse angles have measures
greater than 90° but less
than 180°. T U
V
Q
S
R

10. • if an angle’s measure is
R
180°, it is called a
straight angle.
180
Q
P

11. A. Identify what is being modified in FF.
1. An angle whose measure is exactly 90°.
2. A figure formed by two rays with common endpoint.
3. An angle whose measure is 180 degrees.
4. an angle whose measure is less than 90°.
5. angles have measures greater than 90° but less than 180°.

12. L M
K
J O N
P
A. Use your protractor to measure each angle in the given figure.
1. Angle JOK 6. Angle KOL
2. Angle KOM 7. Angle JOP
3. Angle LON 8.Angle MOL
4. Angle MOP 9. Angle MON
5. Angle POL 10.Angle JOL

13. L M
K
J O N
P
B. (same figure) Tell what kind of angle is each.
1. Angle JOK 6. Angle KOL
2. Angle KOM 7. Angle JOP
3. Angle LON 8.Angle MOL
4. Angle MOP 9. Angle MON
5. Angle POL 10.Angle JOL

14. A. B.
1. 135 1. Obtuse angle
2. 90 2. Right angle
3. 90 3. Right angle
4. 90 4. Right angle
5. 135 5. Obtuse angle
6. 45 6. Acute angle
7. 135 7. Obtuse angle
8. 45 8. Acute angle
9. 45 9. Acute angle
10. 90 10. Right angle