Download - ARC LENGTH
DEPARTMENT OF EDUCATIONDIVISION OF CITY SCHOOLS
ERNESTO RONDON HIGH SCHOOL
MATHEMATICSDEPARTMENT
Featuring: CIRCLE
THE DOODLE GAME
an unfocused drawing made while a person's attention is otherwise occupied. Doodles are simple
drawings that can have concrete representational meaning or may
just be abstract shapes.
*DOODLE
GUESS MY FIGURE 543210
MEXICAN FRYING AN EGG
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A TAHO VENDOR
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AN ICE SCREAM VENDOR
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MEXICAN PLAYING A TRUMPET
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MEXICAN RIDING A BICYCLE
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MEXICAN TAKING A BATH
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MEXICAN COUPLE KISSING
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GIRAFFE PASSING BY THE WINDOW
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KOALA BEAR CLIMBING A TREE
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THREE MEXICANS PEEING
RECALL
How do you call on the distance between the center and a point on the circle?
RECALL
How do you call on the angle whose vertex is at the center and whose sides are the radii of the circle?
RECALL
How do you call on a subset /any part of a circle.
ARCARC
RADIUSCENTRAL ANGLECENTRAL ANGLE
RADIUS
ARC LENGTH
ARC LENGTHit refers to the fractional part of the circumference subtended by the arc in a circle. Radian
measure is used to find the arc length.
GROUP ACTIVITY NO. 4
You are given 7 minutes to answer the activity. Speed and accuracy are
important.
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A
BC
D
E
FG
H
45°
A
B
45°
The arc length (s) is directly proportional to the radius (r) of the circle. While the central angle (Ѳ) is constant.
In equation:s /r = Ѳ
where:s – arc length of the circler – radius of the circleѲ – central angle in
radian measure
s = Ѳ•r
1. Find arc length (s) of the circle illustrated below.
SAMPLE EXERCISE
π/35cms
π/35cm s SOLUTION:s = ѳ • r = π/3 • 5 = 5π/3
ANSWER: s = 5π/3 cm.
2. Find arc length (s) of the circleSAMPLE EXERCISE
100°7cms
SOLUTION:
s = ѳ • r = 5π/9 • 7 = 35π/9
ANSWER: s = 35π/9 cm.
100°7cms
Change the central angle to radian measure
100° x π/180 °5π/9
3. The radius of the circle is 25mm. Find the length of an arc of the circle subtended by a central of 60°.
SAMPLE EXERCISE
SOLUTION:s = ѳ • r = π/3 • 25 = 25π/3mm
60° x π/180 °π/3
SUMMING UP!
What have added inside the coconut shell?
Quiz no. 5Find the arc length of a circle having the radius r and central angle with measure Ѳ.
1. r = 4 feet, Ѳ = π/42. r = 6inches, Ѳ = 330°3. r= 10meters , Ѳ = 150°
ASSIGNMENT
3.82 m
R
Q
P
7.64 in.
18 in.
Z
Y
X
Find the circumference
Find the central angle
Thank You