circumference & arc length of circles. 2 types of answers rounded put mode on classic type the...
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Circumference & Arc Length
of Circles
2 Types of Answers
Rounded• Put mode on
classic• Type the Pi
button on your calculator
• Round
Exact• Put mode on
mathprint• Type the Pi
button on your calculator
• Pi will be in your answer
CircumferenceThe distance around a circle
orC 2 r
C d
Circumference
Find the EXACT circumference.
28 ft1.r = 14 feet
2.d = 15 miles15 miles
C 2 14
C 15
Ex 3 and 4: Find the circumference. Round to the nearest tenth.
89.8 mm 103.7 yd
C 2 14.3 C 33
Work on 5 & 6 in partners.
Arc LengthThe distance along the curved line
making the arc (NOT a degree amount)
Arc Length
measure of arc
Arc Length 2360
r
Ex 7. Find the Arc LengthRound to the nearest hundredths
8m
70
Arc Length 9.77 m
measure of arc
Arc Length 2360
r
70
Arc Length 2 8360
Ex 8. Find the exact Arc Length.
10Arc Length in
3
measure of arc
Arc Length 2360
r
120
Arc Length 2 5360
Ex 9. Find the radius. Round to the nearest hundredth.
B
A
»Arc Length of 3.82AB m=
60◦
3.65 mr
60
3.82 2360
r
1375.2 60 2 r
1375.2 120 r
11.46 r
Ex 10. Find the circumference. Round to the nearest hundredth.
80◦
8032.11 2
360r
11,559.6 80 2 r
144.50inC
»Arc Length of 32.11inAB=
B
A
11,559.6 80 C
Ex 11. Find the radius of the unshaded region. Round to the nearest tenth.
75◦ B
A
»Arc Length of 10AB cm=
75
10 2360
r
3600 75 2 r
3600 150 r
24 r7.6r cm
FYI: Unit 3A Test
Next Tuesday!