What is the arc length of the subtending arc for an angle of 72 degrees on a circle of radius 4?

Question

johnweldon1993 · Answer

Hint $\large s = r\theta $

But you need $ \theta$ in radians to measure

mathstudent55 · Answer

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mathstudent55 · Answer

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mathstudent55 · Answer

You are looking for s.

mathstudent55 · Answer

The arc length of an entire circle is its circumference.
Do you know how to find the circumference of a circle of radius 4?

mathstudent55 · Answer

Find the circumference of the circle. That is the arc length of an arc tended by a 360-deg central angle. Then use a proportion to find what the arc length is for a central angle of 72 deg.

You can also use this formula:

$s = \dfrac{n}{360^o}\cdot 2 \pi r$

or simply

$s = \dfrac{n \pi r}{180^o}$

where n is the measure of the central angle.