23 terms

# Chapter 11 Circles

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Circle
ellipse in which the two axes are of equal length
Center
a point equidistant from the ends of a line or the extremities of a figure
the length of a line segment between the center and circumference of a circle or sphere
Diameter
the length of a straight line passing through the center of a circle and connecting two points on the circumference
Chord
a straight line connecting two points on a curve
Secant
a straight line that intersects a curve at two or more points
Tangent
a straight line or plane that touches a curve or curved surface at a point but does not intersect it at that point
Point of Tangency
the point where a circle and a tangent intersect
Central Angle
an angle whose vertex is the center of the circle
Inscribed Angle
an angle whose vertex is on a circle and whose sides contain chords of the circle
Arc length
a portion of the circumference of a circle
Arc measure
the degree measure of an arc, found by measuring the central angle
Circumference
the length of the closed curve of a circle
Area of a circle
A=πr²
Area of a sector
A sector is a piece of the area of a circle. If n is the degree measure of the sector's central angle then the formula is: Area of a Sector = (n/360) (πr)2
In terms of Pi
3.14
Intercepted arc
the arc that lies in the interior of an inscribed angle and has endpoints on the angle.
Inscribed
a circle (on the inside) of a polygon and only touches each side at exactly 1 point
Congruent
Having the same size and shape
Concentric
arcs and circles that share the same center points
Cyclic
occurring or moving in cycles
Degree
A unit used to measure distances around a circle. One degree equals 1/360 of a full circle.
Semicircle
a plane figure with the shape of half a circle