1. Angle Types
and
Their Measures

2. Some Basic General Info.
Line
Straight, no curve, extends in both directions indefinitely
Line Segment
Straight, no curve, has 2 fixed end points, includes all points between end points.
Ray
Has 1 fixed end point & 1 floating end point, extends in 1 direction indefinitely.
Angle
Has 2 Rays that share a common, fixed end point.

3. There are 4 Basic Types of Angles
Some Basic Angle Info.
There are 4 Basic Types of Angles
Acute, less than 90o
Obtuse, greater than 90o
Right, equal to 90o
Straight, equal to 180o

4. Some Basic Angle Info. (continued)
Angle Arc Mark
The labelling of angles is extremely important. The middle letter of the angle is always the vertex (or common end point) of the angle. A
Vertex of the angle B C
The above angle is written as: 𝑨𝑩𝑪 𝒐𝒓 𝑪𝑩𝑨
or simply as 𝑩

5. Complementary Angles A D C B 𝒎 𝑪𝑩𝑫+𝒎 𝑫𝑩𝑨=𝟗𝟎° 𝑨𝑩𝑪 is Right Angle and
Step 1 – Label the Angles A
Step 2 – Label the Angles with Arc Marks.
Complementary Angles are 2 adjacent angles that equal 90o D C B
𝒎 𝑪𝑩𝑫+𝒎 𝑫𝑩𝑨=𝟗𝟎°
and
𝑨𝑩𝑪 is Right Angle

6. Vertical or Opposite Angles
Formed by 2 intersecting lines.
Step 1 – Label the Angles A D
Vertical or Opposite Angles are Congruent or Equal to each Other B
Step 2 – Label the Opposite Angles with Congruent Arc Marks. C
𝒎 𝑨𝑩𝑪=𝒎 𝑫𝑩𝑬 E
𝒎 𝑨𝑩𝑫=𝒎 𝑪𝑩𝑬

7. Supplementary Angles A D B C E 𝒎 𝑪𝑩𝑨+𝒎 𝑨𝑩𝑫=𝟏𝟖𝟎° 𝒎 𝑨𝑩𝑫+𝒎 𝑫𝑩𝑬=𝟏𝟖𝟎°
Step 1 – Label the Angles A D
𝒎 𝑪𝑩𝑨+𝒎 𝑨𝑩𝑫=𝟏𝟖𝟎°
Step 2 – Label the Angles with their required Arc Marks.
𝒎 𝑨𝑩𝑫+𝒎 𝑫𝑩𝑬=𝟏𝟖𝟎° B C
Supplementary Angles are 2 adjacent angles that equal 180o E

8. Alternate Interior Angles
Step 1 – Label the Angles C B A D
AD and FG are parallel to each other and HC is called a Transversal F G E H
Alternate Interior Angles are Congruent to each Other
𝒎 𝑨𝑩𝑬=𝒎 𝑮𝑬𝑩
𝒎 𝑫𝑩𝑬=𝒎 𝑭𝑬𝑩

9. Corresponding Angles C A D B F G E H 𝒎 𝑪𝑩𝑫=𝒎 𝑩𝑬𝑮 𝒎 𝑪𝑩𝑨=𝒎 𝑩𝑬𝑭
Step 1 – Label the Angles A D B
Step 2 – Add the Congruent Arc Marks for each Corresponding Angle
AD and FG are parallel to each other and HC is called a Transversal F G E H
Corresponding Angles are those that are located in the same positions with respect to each other and thus Correspond to each other
𝒎 𝑪𝑩𝑫=𝒎 𝑩𝑬𝑮
𝒎 𝑪𝑩𝑨=𝒎 𝑩𝑬𝑭

10. Your Turn 1.
Solve the following for “x” and “y” and put your answer on the lines provided: 𝒚
𝟐𝒙+𝟏𝟎
𝒙+𝟑𝟎
𝒙 = _____
𝒚 = _____

11. 2.
Find the measure of each angle and put your answer on the line provided. G
ADB = _______ F
5𝟎°
ADC = _______ E H
BDF = _______
CDF = _______
HFG = _______ D C B
HFD = _______
GFE = _______
DFE = _______ A

12. Your Turn
(Answer Key) 1.
Solve the following for “x” and “y” and put your answer on the lines provided: 𝒚
𝟐𝒙+𝟏𝟎
𝒙+𝟑𝟎
𝒙 = 20
𝒚 = 160

13. (Answer Key) 2.
Find the measure of each angle and put your answer on the line provided. G
ADB = 130 F
5𝟎°
ADC = 50 E H
BDF = 50
CDF = 130
HFG = 50 D C B
HFD = 130
GFE = 130
DFE = 50 A