Geometry Section 10.1
Segments and Lines of Circles
A *circle is a set of points, in a
plane, that are equidistant from a
given point.
This given point is called the
center
______of
the circle. A circle can
be named by using the symbol
_____ and naming the center of
the circle. The circle to the right
is _____.
A *radius (plural: radii) is a
segment from the center to any
point on the circle.
Note: Two circles are congruent if
their radii are congruent.
A *chord is a segment whose two
endpoints are on the circle.
A *diameter is a chord which
passes through the center of
the circle.
Note: The length of a diameter equals
2 times the length of a radius.
A line in the plane of a circle may
or may not intersect the circle.
There are 3 possibilities.
A *secant to a circle is a line which
intersects the circle in 2 points.
Note: Every secant will contain a
chord. Be sure to include the proper
symbol for a segment or line when
naming chords or secants.
A *tangent to a circle is a line, in
the plane of the circle, that
intersects the circle in exactly one
point.