10.1-10.2 Terminology Quiz Flashcards
Interior of a circle
Points inside of a circle
Exterior of a circle
Points outside of a circle
Chord
A segment whose endpoints are on the circle
Diameter
A chord that passes through the center of a circle
Radius
Segment whose endpoints consist of the center of the circle and a point on the circle
Circle
Set of all points in a plane that are equidistant from a given point called the center
Tangent
If a line intersects a circle at exactly 1 point, then the line is a tangent of a circle
Point of tangency
If a line intersects a circle in exactly one point, then the line is A tangent of a circle. This point of intersection is called the point of tangency
Secant
If a line intersects a circle at two points, then the line is a secant of the circle
Common tangent
A line is that tangent to 2 circles
Common external tangent
A common tangent that does not intersect the segment that joins the centers of the circles
Common internal tangent
A common tangent that intersects the segment that joins the centers of the circles
Two circles can intersect in four different ways
1) Who circles can have no points of intersection
2) two circles can have exactly 1 point of intersection
3) two circles can have exactly 2 points of intersection
4) two points can have infinitely many points of intersection
Concentric circles
Circles that have the same center
Congruent circles
Circles with congruent radii or diameters
If a line is tangent to a circle,
Then it is perpendicular to the radius drawn to the point of tangency
In a plane, if a point is perpendicular to a radius of a circle, at its end point on the circle,
Then the line is tangent to the circle
Two segments from the same exterior point are tangent to a circle,
Then they are congruent
Inscribed circle
A circle is inscribed in a polygon if each side of the polygon is tangent to the circle
Circumscribed polygon
A circle is circumscribed about a polygon if each vertex of the polygon lies on the circle
Central Angle
And angle whose vertex is the center of the circle
Minor arc
Consists of the endpoints of the central angle and all points on the circle that are in the interior of the central angle
Measure of a minor arc
The measure of the central angle
Semicircle
An arc whose endpoints are the endpoints of the diameter
Major arc
Consists of the endpoints of the central angle and all points on the circle that lie in the exterior of the central angle
Measure of a major arc
360 - measure of the associated minor arc
Adjacent arcs
Two arcs of the same circle are adjacent if they intersect at exactly one point
Arc addition postulate
The measure of an arc formed by two adjacent arcs is the sum of the measures of the two arcs
Congruent arcs
In the same circle or congruent circles, two arcs are congruent if they have the same measure
In the same circle or in congruent circles, two arcs are congruent iff
Their central angles are congruent
