This document contains notes from a geometry class discussing relationships between chords of a circle. It includes theorems stating that if two chords of a circle are equidistant from the center, they are congruent, and if two chords are congruent, they are equidistant from the center. Examples are provided to demonstrate these theorems. Students are assigned exit slip problems to complete with a partner checking relationships between lengths of chords. Homework problems from the textbook are also listed.

1. Geom10.1­10.2.notebook March 01, 2012
BELL WORK: Chord AB measures A
12 mm and the radius of circle P is
10 mm.
Find the distance from AB to P.
P
B
(The distance from the center of a circle to the chord is the measure
of the perpendicular segment from the center of the chord.)
Theorems from yesterday's intro to circles:
• If a radius is perpendicular to a chord, then it bisects the chord.
• If a radius of a circle bisects a chord that is not a diameter, then it is
perpendicular to that chord.
• The perpendicular bisector of a chord passes through the center of the
circle.
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2. Geom10.1­10.2.notebook March 01, 2012
Homework questions? (p.443 #6,8,11,12,14)
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3. Geom10.1­10.2.notebook March 01, 2012
10.2 ­ Congruent Chords
We are going to talk about some relationships between chords.
Let's do it!
Theorem: If two chords of a circle are equidistant from the
center, then they are congruent.
Theorem: If two chords of a circle are congruent, then they are
equidistant from the center of the circle.
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4. Geom10.1­10.2.notebook March 01, 2012
C
Example:
B
Given: T, AB = CD
Q
T
OP = 12x ­ 5
P
OQ = 4x + 19
D
Find OP.
A
Find a partner near you, complete the following 2 problems as
your exit slip. I must check them and collect them before you
begin your homework:
1. In a circle, chord AB is 325 cm long and chord CD is 3 and
1/4 m long. Which is closer to the center of the circle?
B
Q
2. Given: P, PQ = PR
AB = 6x + 14 A
CD = 4 ­ 4x P
D
C R
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5. Geom10.1­10.2.notebook March 01, 2012
Homework: p.448 #6,11­13
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