GEOMETRY
Unit 9
Name _______________________
TERM
DEFINITION
The set of all points in a plane at a given
distance from a given point, called the
_______________.
symbol: ______
ex. _____
Any ___________ joining the center of the
circle to a point on the circle. All
___________ (plural) are ____________.
ex.
_____
A ___________ whose endpoints lie on a
circle.
ex.
_____
A ___________ that contains the center of
a circle.
ex.
_____
 ____________ = 2 ∙ ___________
 It is the longest chord of any circle!
A ________ that contains a chord of a
circle.
ex. ____
A line in the plane of a circle that intersects
the circle in exactly ______ point.
Sometimes a _______ or ____________.
ex. _____
__________________: point of intersection
PICTURE
The set of all points in _________ at a
given distance from a given point, called
the center.
**The same terms are used as a circle.
Circles (spheres) that have
_________________ radii.
Circles (spheres) that have the same
_____________.
A polygon that is ____________ a circle so
that each of its vertices lie on the circle.
A circle that ______________a polygon so
that each vertex of the polygon lies on the
circle.
 Draw O. Then draw radii OA and OB with length of 6 so that mAOB = 60 angle.
Find the length of AB.
 Draw O. Then draw radii OA and OB with length of 6 so that mAOB = 90 angle.
Find the length of AB.
Unit 9—Circles
Basic Terms HW
NAME: ______________________
Use the picture to identify the following. (Remember notation!)
1) Name 2 chords. ______ _______
N
2) Name two radii. ________ ________
3) Name a tangent. ________
P
J
M
O
4) What is the point of tangency? _______
R
5) Name a secant. _______
K
6) The circle would be called  _____
L
7) Name the diameter. _______
8) If ON = 5 m, find the length of KN. _______
9) If OK = 12.25 cm, find the length of NO. _______
10) Why is RP not a chord? ________________________________________________________
Complete the following.
11)A circle has radius 8, find the diameter. _______
13) A circle has diameter of 6x, find the radius. ______
12)A circle has diameter 13, find the radius. ______
14) A circle has radius of 4√3, find the diameter. _______
15) Draw radii OK and OJ
so that mKOJ = 60 angle.
Find the length of JK if OK=10.
16) Use the picture to find the length of AB.
AOB=120˚ Hint Look for Special Right ’s!!
B
O
12
A