On a circular track of radius (63) m what is the distance covered for a central angle of (40^\circ)?
Answer and explanation
Correct answer: \(14\pi\) m
The arc-length formula is \(s=r\theta\), where \(\theta\) must be in radians. \(40^\circ=40\times\frac{\pi}{180}=\frac{2\pi}{9}\) radians. Therefore, \(s=63\times\frac{2\pi}{9}=14\pi\) m. Hence, \(14\pi\) m is correct. A nearby distractor such as \(16\pi\) m can result from an incorrect degree-to-radian conversion or multiplication. Exam tip: always convert the angle to radians before applying the arc-length formula.
Frequently asked questions
What is the correct answer to this question?
\(14\pi\) m
Why is this the correct answer?
The arc-length formula is \(s=r\theta\), where \(\theta\) must be in radians. \(40^\circ=40\times\frac{\pi}{180}=\frac{2\pi}{9}\) radians. Therefore, \(s=63\times\frac{2\pi}{9}=14\pi\) m. Hence, \(14\pi\) m is correct. A nearby distractor such as \(16\pi\) m can result from an incorrect degree-to-radian conversion or multiplication. Exam tip: always convert the angle to radians before applying the arc-length formula.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Trigonometric Functions. Topic: Angles.
