Chapter 10 Flashcards
Chord
A segment whose endpoints are on a circle
Cirle
Set of. All points in a plane that are equidistant from a certain point called the center. The points inside the circle form it’s interior. The points outside the circle form it’s exterior.
Diameter
A chord that passes through the center
Radious
A segment that has a center as one endpoint and a point on the circle as another
Tangent
A line that intersects a circle at exactly one point
Point of tangency
The point at which the tangent intersects
Secant
A line that intersects a circle at two points
Common tangent
A line that is tangent to two 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
Concentric circles
Circles that have the same center
Congruent circles
Circles with congruent radii or diameters
Thm 10.1
If a line is tangent to a circle then it is perpendicular to the radio us drawn to the point of tangency
Thm 10.2
In a plane, if a line is perpendicular to a radius of a circle at its endpoints on a circle then the line is tangent to the circle
Thm 10.3
If 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 a polygon is tangent to a circle