Chord
Pronunciation: /kÉ”rd/ Explain
Click on the blue points and drag them to change the figure. Click on the check boxes to see different attributes of a chord.
Describe the chord with an apothem that is zero length.
Describe the chord with a sagitta that is zero length.
 Manipulative 1  Chord Created with GeoGebra. 

A chord is a line segment joining two distinct points
on a curve, usually a circle.^{[2]}
An apothem
is a line segment extended from the bisector of the chord to the center of
the circle.^{[2] page 110} A
sagitta
extends from the bisector
of the chord to the edge of the circle in the same line as the apothem.
Any angle whose vertex is on the circle and whose legs pass through the end points
of the chord is a subtended angle of the chord.
The arc cut off by the chord is called the arc of the chord.

Properties of Chords
 The perpendicular bisector
of a chord passes through the center of the circle.
 The apothem
and sagitta
of a chord together make a
radius
of the circle.
 All angles that subtend the end points of the chord on the same side of the chord
are equal.
 A chord is a diameter of the circle
if and only if
it passes through the center of the circle.
 Chords are
equidistant
from the center of the circle
if and only if
they are the same length.
References
 McAdams, David E.. All Math Words Dictionary, chord. 2nd Classroom edition 201501084799968. pg 33. Life is a Story Problem LLC. January 8, 2015. Buy the book
 Keller, Samuel Smith. Mathematics for Engineering Students, Plane and Solid Geometry. 2nd edition. pg 4647. www.archive.org. D. Van Nostrand Company. 1908. Last Accessed 6/25/2018. http://www.archive.org/stream/mathengineer00kellrich#page/46/mode/1up/search/chord. Buy the book
Cite this article as:
McAdams, David E. Chord. 4/13/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/c/chord.html.
Image Credits
Revision History
4/13/2019: Corrected references. (
McAdams, David E.)
3/5/2019: Improved manipulative. Added word links. (
McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (
McAdams, David E.)
6/25/2018: Removed broken links, updated license, implemented new markup, updated GeoGebra apps. (
McAdams, David E.)
1/11/2010: Added "References". (
McAdams, David E.)
11/25/2008: Initial version. (
McAdams, David E.)