1. 1.4 Angles Measure
CCSS:
G-CO.1 Experiment with transformations in the plane.
G-CO.12 Make geometric constructions.
Objective:
Measure and classify angles

2. Ray: is a part of a line, it has an endpoint (starting point) and extends indefinitely
Named EF, or EG E Q P P R
Opposite Rays by definition are two collinear rays with a common endpoint

3. Angle An angle is formed by two non-collinear rays
(called the sides) with the same initial point
(called the vertex) C
Vertex: point A
Ray
(Side)
Sides: AB, and AC B A
Ray (Side)
Vertex

4. Naming Angles There are three ways to name angles C B A 4
1. By using the vertex
2. By using the points
on the angle C 4 B
3. By using the number
inside the angle A

5. Interior and Exterior of Angles
An angle divides a plane into 3 distinct parts. On, In, or Outside ON
Points A, D, and E lie _____________
the angle M IN
Points C and B lie _____________
of the angle A C
OUTSIDE B
Points F and G lie _____________
of the angle E F D G

6. Example 1 p. 32 Angles and Their PartsW X V
Name all the angles that have
W as a vertex 2 1 3
Name the side of <1 5 4 Z Y
Write another name for <WYZ

7. Notes #2 (1.4) continued 1.4 Angles Measure
CCSS:
G-CO.1 Experiment with transformations in the plane.
G-CO.12 Make geometric constructions.
Objective:
Measure and classify angles
Identify and use congruent angles and the bisector of an angle

8. Protractor Since QP is aligned It has two scales running
w/ 0 the other side
of the angle can be measured at 65 degrees
It has two scales running
from 0 to 180 degrees in
opposite directions
Align the 0 on either
side of the angle
The center point of the protractor
is on the vertex

9. Classifying Angles
90 < m C < 180

10. Congruent Angles ~ m<A = m<B <A = <B
Congruent Angles: are angles with the same measure or degree
Angle congruence looks like this… ~
m<A = m<B
<A = <B D B C A

11. Example
In the figure, If
and
Find the measurements of A C B D F

12. Angle Bisector: a ray that divides an angle into two congruent angles
Angle Addition
When a line divides an angle into two smaller angles
Then the sum of the smaller angles equals the larger angle m< RSP + m<PST = m<RST R P S T