Download Postulate 3: Protractor Postulate 1.4 Measure and Classify Angles

1.4 Measure and Classify Angles
vocab
angle two rays with the same endpoint
sides rays are the sides of an angle
vertex the endpoint of the rays is called
the vertex of the angle
vertex
Postulate 3: Protractor Postulate
m<AOB = 140
o
translation:
The measure of angle AOB, where
A and B are endpoints and O is
the vertex, equals 140 degrees
sides
acute angle o
o
0 < m<A <90
right o
m<A = 90
obtuse angleo
o
90 < m<A <180
straight angle o
m<A = 180
K
**Discussion on
naming angles!!**
J
L
N
M
List all of the possible angles above and their angle measures.
Postulate 4: Angle Addition Postulate
Does this hold true for the angles we just looked at?
?
o
If m<ADC = 72 , then find m<ADB and m<BDC.
(2x
- 9) o
C
(3
x
+
6)
o
B
D
L
(4
x
+
3)
o
A
K
(10
xN
5)
o
M
If m<KNM is a straight angle, then find m<KNL and m<NLM.
If m<ADC is a right angle, then find m<ADB and m<BDC.
B
7)
(3x
C
o
(2x - 3) o
A
D
congruent angles angles that have the same measure
Translations:
angle bisector a ray that divides an angle into two congruent angles
X
Y
W
Identify the parts in
the figure above:
vertex sides angle bisector -
Write a formula for
finding m<XWZ.
Z
Write a formula for
finding m<XWY.
o
If m<XWZ is 62 and WY is an
angle bisector, find m<YWZ.
o
If m<XWY is 49 and WY is an
angle bisector, find m<XWZ.
homework:
p 28: 3, 5, 6, 7-24 even, 25, 26, 29, 31, 33-38 all, 50, 56 - 61 even