Notes on 10-1

1. CIRCLES
SECTION 10-1
JIM SMITH JCHS

2. .
A CIRCLE IS
A SET OF POINTS
EQUIDISTANT
FROM A GIVEN
POINT CALLED
THE CENTER
DEFINITION

3. PARTS OF A CIRCLE
CENTER
A
Circles are named
by their center
o A

4. PARTS OF A CIRCLE
RADIUS
RADII
DISTANCE
FROM CENTER
TO CIRCLE

5. PARTS OF A CIRCLE
CHORDS
ENDPOINTS ARE
ON THE CIRCLE

6. PARTS OF A CIRCLE
A
DIAMETER
CHORD THAT
CONTAINS
THE CENTER

7. PARTS OF A CIRCLE
A
d = 2r
r = d / 2

8. DIAMETERS OF CIRCLES A,
B, and C ARE 14, 20, and 10
B
A
X Y
C
FIND XB FIND BY

9. B
A X Y C
FIND XB
XB = AB- AX
XB = 10 – 7
XB = 3
FIND BY
BY = BC – CY
BY = 10 – 5
BY = 5

10. CIRCUMFERENCE
C = 2 π r or C = d π
1) FIND C if r = 7
C = 2 π 7
C = 14 π or 43.96
2) FIND C if d = 12
C = 12 π or 37.68

11. 5
5
FIND THE CIRCUMFERENCE
EXACT ANSWER
NEAREST TENTH

12. 5
5
45,45,90 TRIANGLE
d = 5√2
EXACT ANSWER
C = 5√2π
NEAREST TENTH
C = 22.2