7-6 circles & arcs 7-7 area of circles and sectors
TRANSCRIPT
7-6 Circles & Arcs7-7 Area of Circles and Sectors
Vocabulary
A
G
E
B
C D
F
Circle A or A
Radius AB, AE, AF
Diameter BE
Chord CD, BE
Vocabulary
Circle = 360
Arc: BGE, EF, FB, FBG
Minor Arc (less than 180 ) BF, FE, EG, GB
Major Arc (more than 180)
FBG, FBE, GEB
Semicircle (equals 180)
BGE, BFE
A
G
E
B
F
Vocabulary
Central Angle – angle whose vertex is the center of the circle
<BAF, <FAE
A
G
E
B
F
Vocabulary & Formulas
Concentric Circles – circles that have same center.
Circumference – distance around circle
C = 2r or C = d
Area A =r2
H
JI
K
Length of an Arc: what’s the formula?
75
FormulasMeasure of an
arc is always in degrees
measure of arc = central angle
Arc Length is always in dimensions
2 r360
mL
Area of Sector: What is the formula?
75
Formula
360
mArea of a Sector
A = r2
Formula
Area of a segment
Segment
1) Find area of Sector2) Find area of Triangle3) Area of Segment = area of
sector minus area of triangle
Examples5) Find mFG
6) Find mIJH
7) Find mFIG
8) IF JG=5cm, find the
length of GFI
8050
FG
I
H
Examples
1) If KJ = 5 find the area of circle K.
2) If = 120 and
KL = 6, what is the area of sector JKL?
3) If m<JKL = 135 and
KJ = 2, what is the area of sector JKL?
mJL K
J
L
Examples: Find area of segment.
O B
A
8
60