Suppose S is between R and T. Use the Segment Addition Postulate or sum of the parts = whole or the add two parts of a line together thing to solve for the variable.

1
Suppose S is between R and T. Use the Segment
Addition Postulate or sum of the parts whole or
the add two parts of a line together thing to
solve for the variable.
RS 12, ST 2x, RT 34
1.
RS 16, ST 2x, RT 5x10
2.
RS 4y-1, ST 2y-1, RT 5y
3.
RS 2z6, ST 4z-3, RT 5z12
4.
2
Find the value of the variable and PB, if P is
between A and B.
A
P
B
AP-2s, PBs8, AB11
1.
3
Lesson 1-4
Learners will be able to measure and classify
angles, congruent angles, and angle bisectors.
4
A ray is a part of a line. It has one endpoint
and extends indefinitely in one direction.
X
Y
X
Y
Rays are named stating the endpoint first and
then any other point on the ray.
5
If you choose a point on a line, you make exactly
two rays called opposite rays.
X
Y
Z
Y
X
Y
Z
Name the 2 Rays
6
An angle is the intersection of two noncollinear
rays at a common endpoint.
The common endpoint is called the vertex, and the
rays are the sides of the angle.
7
An angle can be named by a single letter ex ?B
A
B
C
Or by three letters a point on one side, the
vertex, and a point on the other side. ex ?ABC
8
Example 4-1a
Name all angles that have B as a vertex.
Answer ?5, ?6, ?7, and ?ABG
9
Example 4-1b
Name the sides of ?5.
10
Example 4-1c
Write another name for ?6.
Answer ?EBD, ?FBD, ?DBF, and ?DBE are other
names for ?6.
11
Example 4-1d
Answer ?1, ?2, ?3, and ?RXB or ?RXN
Answer ?AXB, ?AXN, ?NXA, ?BXA
12
There is an interior and an exterior of an angle
A
Z
B
C
W
Where is point Z? W? C?
13
Angles are measured in degrees.
What are degrees?
Da sun
1 of a circle
360
14
A right angle is an angle with a measurement of 90
Logically where is a 45 angle?
15
There are two other types of angles beside right
angles.
90 lt m?ABC lt 180
A
C
B
Obtuse which have a measurement greater than 90
16
There are two other types of angles beside right
angles.
A
m?ABC lt 90
C
B
Acute which have a measurement lesser than 90
17
Example 4-2a
Measure ?TYV and classify it as right, acute,
or obtuse.
?TYV is marked with a right angle symbol, so
measuring is not necessary.
18
Example 4-2b
Measure ?WYT and classify it as right, acute, or
obtuse.
19
Example 4-2d
Answer 150, obtuse
Answer 90, right
Answer 30, acute
20
Just like with congruent sides we also have
congruent angles
A
C
B
21
A ray or line that divides an angle into two
congruent angles is called an angle bisector
A
C
B
22
A ray or line that divides an angle into two
congruent angles is called an angle bisector
A
C
B
23
Example 4-3a
24
Example 4-3b
Given
Definition of congruent angles
Substitution
Add 10 to each side.
Subtract 2x from each side.
25
Example 4-3c
Use the value of x to find the measure of one
angle.
Given
or 35
Simplify.
26
Example 4-3d
27
HomeworkLesson 1-4, p. 33 4-36 even42, 50