10-1Circles and Circumference

1
10-1Circles and Circumference
You identified and used parts of parallelograms.

• Identify and use parts of a circle.

• Solve problems involving the circumference of a
  circle.

2
Definition
center
A circle is the locus of points in a plane
equidistant from a given point. That point is
the center of the circle.
3
Circle Parts
radius
diameter
?Q
?Q
A circle is named by its center. A radius is a
segment from the center to any point on the
circle. A diameter is a segment that contains the
center of the circle and has endpoints on the
circle.
4
Definition
A
A chord is a line segment that joins two points
on a circle. AB is a chord of ?D Where would you
find the largest chord in any circle?
B
D
5
p. 697
6
A. Name the circle and identify a radius.
7
B. Identify a chord and a diameter of the circle.
8
A. Name the circle and identify a radius.
9
B. Which segment is not a chord?
10
By definition, the distance from the center of a
circle to any point on the circle is always the
same. All radii of a circle are congruent. A
diameter (d) is made is made up of two radii.
1 raduis
1 raduis
p. 698
11
d 2r Diameter Formula 21 2r d 21 10.5
r Simplify.
Answer QV 10.5 cm
12
A. 12 cm B. 13 cm C. 16 cm D. 26 cm
13
Exterior, Interior, Concentric
exterior
Concentric circles are two coplanar circles with
the same center.
interior
14
p. 698
15
5
 
 
 
 
16
A. 3 in. B. 5 in. C. 7 in. D. 9 in.
17
10-1 Assignment Day 1
p. 701, 10-21