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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
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
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
Example
Find the length of .
BU

B
L
U
E
2
5
x
Example
Find the length of .
BU

B
L
U
E
3
2
5
2 2 2
3 5
x
+ =
x
x = 4
BU = 2(4) = 8
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
A while back, I needed to find the center of a circle, so I used
this property.
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.
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!
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
=
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
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
=
Example
Find the value of x.
10
x
8
12
( ) ( )
10 10 12 20
10 100 240
10 140
14
x
x
x
x
+ =
+ =
=
=
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
=
Example
Find the value of x.
8
10
x
( )
( )( )
2
2
2
10 8 8
18 8
144
12
x
x
x
x
+ =
=
=
=

More Related Content

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
  • 4. Example Find the length of . BU B L U E 2 5 x
  • 5. Example Find the length of . BU B L U E 3 2 5 2 2 2 3 5 x + = x x = 4 BU = 2(4) = 8
  • 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 + = = = =