1. The document discusses properties of chords, secants, and tangents of circles, including: if a radius or diameter is perpendicular to a chord it bisects the chord and arc; if one chord is a perpendicular bisector of another it is a diameter; and the chord-chord, secant-secant, and secant-tangent products.
2. Examples are provided to demonstrate finding lengths and values using these properties, such as finding the diameter or value of x given lengths of line segments.
3. The document also describes how the property of a perpendicular bisector being a diameter was used to find the center of a circle by measuring the midpoint.
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10.3 Chords and Segment Relationships
1. Chords and Segment Relationships
The student is able to (I can):
Apply properties of chords
Find the lengths of segments formed by lines that
intersect circles
2. In the same circle (or in congruent circles), two minor arcs
are congruent if and only if their corresponding chords are
congruent.
E
R
O
F
m m
FO RE
FO RE
3. If a radius or diameter is perpendicular to a chord, then it
bisects the chord and its arc.
ER GO
G
E
O
R
A
GA AO
GR RO
6. If one chord of a circle is a perpendicular bisector of another
chord, then the first chord is a diameter.
The midpoint of the diameter would be the center of
the circle.
G
W
O
N
A
If is a bisector
of , then is a
diameter.
WN
GO WN
7. A while back, I needed to find the center of a circle, so I used
this property.
8. A while back, I needed to find the center of a circle, so I used
this property.
Step 1: I drew
a chord
Step 2: I drew the
perpendicular bisector,
which is a diameter.
9. A while back, I needed to find the center of a circle, so I used
this property.
Step 3: I measured and
found the midpoint of the
diameter, which gave me
the center!
10. chord-chord product if two chords intersect in the interior
of a circle, then the products of the lengths of the
segments of the chords are equal.
S
P
A
C
E
P
S E
A AC A A
=
11. Examples
1. Find the value of x.
2. What is the diameter of the circle?
9 12
x
6 ( )
9 6 12
x =
9 72
x =
8
x =
( )
4 6 6
x =
4 36
x =
9
x =
diameter 4 9 13
= + =
6
6
4
x
12. secant-secant product if two secants intersect in the
exterior of a circle, then the product of the lengths of
one secant segment and its external segment equals
the product of the lengths of the other secant
segment and its external segment.
(whole outside = whole outside)
O
P
M
E
T
M
T O
M EM M P
=
13. Example
Find the value of x.
10
x
8
12
( ) ( )
10 10 12 20
10 100 240
10 140
14
x
x
x
x
+ =
+ =
=
=
14. secant-tangent product if a secant and a tangent intersect
in the exterior of a circle, then the product of the
lengths of the secant segment and its external
segment equals the length of the tangent segment
squared.
(whole outside = tangent2)
G
O
R
F
2
FO RO GO
=
15. Example
Find the value of x.
8
10
x
( )
( )( )
2
2
2
10 8 8
18 8
144
12
x
x
x
x
+ =
=
=
=