AGENDA

1
AGENDA

1. Notes on Circles
2. Notes on Central Angles
3. Practice Worksheet
4. Homework Worksheet

2
Unit 3 Circles
3
Segments of Circles
4
Parts of a Circle
Circle set of all points _________ from a given
point called the _____ of the circle.
equidistant
C
center
Symbol
5
CHORD
A segment whose endpoints are on the circle
6
Radius
RADIUS
Segment from the center to point on circle
P
7
Diameter
DIAMETER
A Chord that passes through the center.
P
Also known as the longest chord.
8
D ?
32
24
12
r ?
16
r ?
4.5
6
D ?
12
9
9
Use ?P to determine whether each statement is
true or false.
10
Secant Line
intersects the circle at exactly TWO points
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Tangent Line
a LINE that intersects the circle exactly ONE time
Forms a 90angle with a radius
Point of Tangency The point where the tangent
intersects the circle
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Name the term that best describes the notation.
Secant
Radius
Diameter
Chord
Tangent
13
Central Section 6.2 Arcs
14
Central Angle
An Angle whose vertex is at
the center of the circle
A
Minor Arc
Major Arc
More than 180
Less than 180
P
C
To name use 2 letters
To name use 3 letters
B
?APB is a Central Angle
15
Semicircle An Arc that equals 180
To name use 3 letters
E
D
P
F
16
THINGS TO KNOW AND REMEMBER ALWAYS
A circle has 360 degrees A semicircle has 180
degrees Vertical Angles are Equal
17
measure of an arc measure of central angle
A
E
96?
Q

96
B
C

264

84
18
Arc Addition Postulate
A
C
B
19
Tell me the measure of the following arcs.
240?
A
D
140?
260?
m BCA
R
40?
100?
80?
C
B
20
CONGRUENT ARCS
Congruent Arcs have the same measure and MUST
come from the same circle or of congruent circles.
C
B
D
45
45
110
A
Arc length is proportional to r
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Classwork

• Practice Worksheet

22
Homework

• Practice Worksheet