More Examples of Arc Length
Let’s work through a couple more examples finding arc length.
Example:
Find the arc length of an arc with measure 200° on a circle with diameter 40 cm.
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Circle with radius 40 centimeters |
Solution:
The length of the arc is approximately 69.81 cm.
Example:
Find the distance two-thirds of the way around a circle with radius 15 m.
Circle with radius 15 meters
Solution:
C = 2πr = 2π(15) = 30π in.
Multiply the fraction by the circumference. 
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Two-thirds of the way around a circle with radius 15 m is 20π m.
Example:
Find the measure of an arc with radius 12 and arc length 5π ft.
Solution:
In this problem, we are given the arc length and asked to find the measure. Use a variable ‘x’ in place of the arc measure and solve for x.
The arc measures 75°.
