find arc measures
Post on 05-Jan-2016
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P
A
BC
Central Angle : An Angle whose vertex is at the center of the
circleMinor ArcMajor Arc
Less than 180°
More than 180°
ABACB
To name: use 2 letters
To name: use 3 letters
APB is a Central Angle
P
E
F
D
Semicircle: An Arc that equals 180°
EDF
To name: use 3 letters
THINGS TO KNOW AND REMEMBER ALWAYS
A circle has 360 degrees
A semicircle has 180 degrees
Vertical Angles are Equal
A
C
BD
A C
B D
measure of an arc = measure of central angle
A
B
C
Q 96m AB
m ACB
m AE
E
=
=
=
96°
264°
84°
Ð EQA is a central angle.
If Ð EQA is 80° then EA = 80°
Arc Addition Postulate
A
B
C
m ABC =
m AB + m BC
Arc Addition Postulate: The measure of an arc formed by two adjacent arcs is the sum of the measures of the two arcs.
Tell me the measure of the following arcs.
80100
40
140A
B
C
D
R
m DAB =
m BCA =
240
260
PQ has a measure of 90° in R.
Find the length of PQ
R Q
P
6P
Q
R12
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