| Math Open Reference | search | Home Index About Contact |
|
Arc Length
Definition: The distance along the curved line making up the arc
Try this Drag one of the orange dots that define the endpoints of the blue arc.
The arc length will be continuously calculated.
(If there is no image below, see support page.)
The arc length is the measure of the distance along the curved line making up the arc.
It is longer than the straight line distance between its endpoints (which would be a
chord)
The formula the arc measure is:
Recall that 2πR is the circumference of the whole circle, so the formula simply reduces this by the ratio of the arc angle to a full angle (360). By transposing the above formula, you solve for the radius, central angle, or arc length if you know any two of them. An interesting side note:
In the figure above, press reset. Notice that the radius and arc length are the same - they both 10.0.
This is because the initial central angle has been set to one radian. (57° when rounded to the nearest degree),
thus demonstrating a definition of a radian: "the angle subtended at the center by an arc whose arc length is equal to the arc's radius".
Other circle topicsGeneral
Angles in a circleArcs
(C) 2007 Copyright John Page
|
