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Area and Length, Page 10

Circular Arc: Example

Let’s look at an example.

Given a central angle of 130°, find the length of the intercepted arc in a circle with radius of 7 cm.

The first step is to change your degree measure into radians:

130 degrees times pi over 180 degrees = 13pi/18

Next, use the formula for finding the length of an arc:

s = rθ; s = (7)(13pi/18)

Use your calculator and round your answer to the nearest tenth.

s = 15.9 cm