释义 |
ChordThe Line Segment joining two points on a curve. The term is often used to describe a Line Segment whoseends lie on a Circle. In the above figure, is the Radius of the Circle, is called theApothem, and the Sagitta. The shaded region in the left figure is called a Sector, and the shaded region in the right figure is called a Segment.
All Angles inscribed in a Circle and subtended by the same chord are equal. The converse is alsotrue: The Locus of all points from which a given segment subtends equal Angles is a Circle.
Let a Circle of Radius have a Chord at distance . The Area enclosed by the Chord, shownas the shaded region in the above figure, is then
 | (1) |
But
 | (2) |
so
 | (3) |
and
Checking the limits, when , and when ,
 | (5) |
See also Annulus, Apothem, Bertrand's Problem, Concentric Circles,Radius, Sagitta, Sector, Segment
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