## anonymous one year ago What is the arc length of the subtending arc for an angle of 72 degrees on a circle of radius 4?

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1. johnweldon1993

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

2. mathstudent55

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3. mathstudent55

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4. mathstudent55

You are looking for s.

5. mathstudent55

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

6. mathstudent55

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.