Download Section 1-1 - winegardnermathclass

Section 1-4
Pages 31-38
Angle Measure
After today’s lesson you should be able to:
- Measure and classify angles.
- Identify and use congruent angles and the bisector of an
angle.
B
A
4
C
An angle is formed by two non-collinear rays that have a common
endpoint. This angle can be named LA, LBAC, LCAB, or L4.
Ex. 1: Name the vertex, the sides, and another name.
Vertex (L1): ______
B
A
C
3
Sides (L3): ____________
Name L3 : _______
D
1
2
An angle divides a plane into three parts:
- Points that lie on the angle.
- Points that lie in the interior.
- Points that lie in the exterior.
- Opposite rays form a straight line which measures 180 degrees.
- Right angles measure 90 degrees.
- Congruent angles are angles that have the same measure.
- An angle bisector splits an angle into two congruent angles.
Ex. 2: In the figure CB and CD are opposite rays, CE bisects
LDCF, and CG bisects LFCB. If mLDCE = 4x + 15 and
mLECF = 6x – 5, find mLDCE.
E
D
C
F
G
B
Ex. 3: QS bisects LPQT, and QP and QR are opposite rays. If
mLPQT = 60 and mLPQS = 4x + 14, find the value of x.
T
S
R
P
Q