Geometry
Notes Lesson 10.6
Name __________________________________
Circle Terminology:
A circle is the set of all points equidistant from a given
point called the center.
______________________
A radius is a segment that has one endpoint at
the center and the other endpoint on the circle.
_____________ ____________ _____________
A diameter is a segment that contains the center of a circle and has endpoints on the circle. _________
A central angle is an angle whose vertex is the center of the circle. __________
Example.
The graph the to right shows how 3600 people
spend their time in a 24-hour period.
What is the total number of degrees in a circle? _____________
18% spend their time on Entertainment. How many degrees is 18%? ____________
Sleep? ________
Food? _________
Arc Terminology:
An arc is a part of a circle. A Semicircle _______________________________________
A Minor arc _____________________________________ A Major arc _________________________________________
_________ is semicircle
_______ is minor arc
_______ is major arc
Degrees of Arcs:
Semicircle = __________
Minor Arc _________________________
Major Arc _______________________
_____________________
__________________________________
________________________________
Example
In
C,
and
are diameters. Identify the following.
two major arcs
two minor arcs
two semicircles
a pair of adjacent arcs
an acute central angle
an obtuse central angle
Example
Find the measure of each arc in
C.
Circumference of a Circle:
Definition: The circumference is the ________________________________________________________________________.
Formula: C = _______________ or C = _______________
Examples
Find the circumference of the circle. Leave your answers in terms of
.
The diameter of a bicycle wheel is 22 in. To the
nearest whole number, how many revolutions
does the wheel make when the bicycle travels
100ft?
Arc Length:
Arc Length =
measure of the arc
 2 r
360
Example
Find the length of each arc. Leave your answers in terms of
Find the length of a semicircle with radius 1.3m.
Leave your answers in terms of  .
.