Objective To solve problems involving circles'

1
Objective - To solve problems involving circles.
Circle -
The set of infinite points equidistant from a
center point.
C
- Center
A
X
- Radius
- Segment or distance from center to
circle.
O
- Chord
- Segment that connects one point on
circle to another.
Y
- Diameter
- Chord that passes through the
center.
M
- Arc
- Piece of a circle.
- Angle whose vertex is
the center.
- Central Angle
- Semicircle
- Half of a circle.
2
Relationship Between Diameter and Circumference
- Two easiest things to measure on a circle.
Silver Dollar
diameter
Circumference
12.0
3.8 cm
12.0 cm
3.8
Compact Disc
37.7
12.0 cm
37.7 cm
12.0
Table Top
628.3
200 cm
628.3 cm
200
3
Relationship Between Diameter and Circumference
- Two easiest things to measure on a circle.
Silver Dollar
Regardless of the size of the circle, the
ratio of the circumference to the diameter
remains constant.
Compact Disc
C
d
Table Top
4
Circumference of a Circle
C
(d) (d)
d
Find the circumference of a circle with a
diameter of 7 inches.
5
Find the missing information.
radius
diameter
Circumference
5 in.
d 2r
10 in.
4 m
8 m
6
Find the missing information.
radius
diameter
Circumference
7 mi.
d 2r
14 mi.
7
Area of a Circle
r
r
r
r
r
8
Find the area of the circles below.
1)
2)
6 in.
16 m
9
Estimate the area of the circle using the
centimeter grid below, then find the area using
Formula
r 4
Estimate
16
4(4)
4(1.5)
4(3)
Close!
16 16 6 12
10
Find the missing information.
radius
diameter
Area
4 yds.
d 8 yds.
11
Area of Sectors
Find the area of the sector below.
1)
4 ft.
12
Area of Sectors
Find the area of the sector below.
2)
9 in.