If \(\theta=4\) radians and \(r=7\) cm then what is the arc length (s)?
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Answer and explanation
Correct answer: 28 cm
For a central angle measured in radians, the arc-length formula is \(s=r\theta\). Thus, \(s=7\times4=28\) cm. The value 14 cm is only twice the radius; arc length must also be multiplied by the angle \(\theta\). Exam tip: use \(s=r\theta\) directly only when \(\theta\) is in radians.
Frequently asked questions
What is the correct answer to this question?
28 cm
Why is this the correct answer?
For a central angle measured in radians, the arc-length formula is \(s=r\theta\). Thus, \(s=7\times4=28\) cm. The value 14 cm is only twice the radius; arc length must also be multiplied by the angle \(\theta\). Exam tip: use \(s=r\theta\) directly only when \(\theta\) is in radians.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Trigonometric Functions. Topic: Angles.
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