Circles and Circumference
Match the parts of the circle to their matching positions
Diameter
?
Radius
?
Chord
?
Center
?
The diameter of a circle, d, is equal to two times the radius.                                   d=2r 
A
B
If AB = 5, what is the
 diameter of the circle?
AB = rAB = 5r=5d= 2(r)d = 2(5)d =
The diameter of a circle, d, is equal to two times the radius.                                   d=2r 
A
B
If AB = 8, what is the diameter of the circle?
d = 
Circumference is the distance around a circle. Like the perimeter, but for circles.The formula for circumference is 2 times pi(3.14) timesthe radius of the circle.
C = 2πr
A
B
AB = 4  inC = 2πr  inC = 2π(4)  inC = 2 (4) (3.14)  inC =   25.12  in
A
B
Find C when AB = 25
C =                   
Pi already here
Find the Radius, Diameter, and Circumference of each 
problem below.
1. C = 15π

2. d = 6
3. r = 7
d =                    r =         
C =                        r= 
C =                       d= 
Find each measureif diameter AB = 16
CB = 
CE = 
DF =
Circumference of circle C =                           
Circumference of circle D =                            
A
C
D
F
E
B
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