Pronunciation: /ɑɹk/ Explain
|Figure 1: Arcs on a Circle||
An arc is any smooth curve joining two
This article will focus on arcs of
An arc of a circle is sometimes called a circular arc.
Any two points on a circle define two arcs. If the two points are on a
of the circle, each arc is called a semicircle. If the two
points are not on a diameter of a circle, they define two arcs. The larger arc
is called the major arc, and the smaller arc is called the
Adjacent arcs are two arcs that share an endpoint.
Arcs are measured based on what portion of a whole circle they occupy. A whole circle
measures 360° or
'rad' is an abbreviation for radians.
An arc occupying 1/2 of a circle would then measure
360° / 2 = 180° or
2π rad / 2 = π rad.
Click on the blue points and drag them to change the figure.|
What is the arc length of a arc of a circle with circumference 4 that covers 90 degrees?
|Manipulative 1 - Arc Length Created with GeoGebra.||
Arc length is defined as the linear length of an arc.
For arcs of circles, the arc length is calculated as a portion of the total
circumference of a circle.
if the arc measures 72°, and the circumference is
the arc length is 72°/360° · 22cm = 4.4cm.
- McAdams, David E.. All Math Words Dictionary, arc. 2nd Classroom edition 20150108-4799968. pg 18. Life is a Story Problem LLC. January 8, 2015. Buy the book
- Arc length. www.khanacademy.org. Kahn Academy. 6/19/2018. https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-arc-length-deg/e/circles_and_arcs.
Cite this article as:
McAdams, David E. Arc. 4/11/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/a/arc.html.
4/11/2019: Changed equations and expressions to new format. (McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)
6/14/2018: Removed broken links, changed Geogebra links to work with Geogebra 5, updated license, implemented new markup. (McAdams, David E.)
3/2/2010: Added sentence on adjacent arcs. (McAdams, David E.)
1/2/2010: Added "References". (McAdams, David E.)
11/12/2009: Added arc length. (McAdams, David E.)
6/11/2008: Added paragraph on the measure of an arc. (McAdams, David E.)
6/7/2008: Corrected spelling. (McAdams, David E.)
4/18/2008: Initial version. (McAdams, David E.)