http://www.ck12.org Chapter 9. Circles
Because the diameter is perpendicular to the chord, it also bisects the chord and the arc. Set up an equation forxand
y.
( 3 x− 4 )◦= ( 5 x− 18 )◦ y+ 4 = 2 y+ 1
14 ◦= 2 x 3 =y
7 ◦=xWatch this video for help with the Examples above.
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/80760CK-12 Foundation: Chapter9ChordsinCirclesB
Concept Problem Revisited
In the picture, the chords from
⊙
Aand⊙
Eare congruent and the chords from⊙
B,⊙
C, and⊙
Dare also
congruent. We know this from Chord Theorem #1. All five chords are not congruent because all five circles are not
congruent, even though the central angle for the circles is the same.
Vocabulary
Acircleis the set of all points that are the same distance away from a specific point, called thecenter. Aradiusis
the distance from the center to the outer rim of a circle. Achordis a line segment whose endpoints are on a circle.
Adiameteris a chord that passes through the center of the circle.
Guided Practice
- Is the converse of Chord Theorem #2 true?
- Find the value ofx.