Question

What is the length of an arc which subtends angle $\theta$ (degrees) at the centre in a circle of radius r?

• A. (πrθ)/180
• B. (πrθ)/360
• C. (πrθ)/60
• D. (πrθ)/90

Answer 1

The correct option is A

(πrθ)/180

For an angle of ${360}^{\circ }$ subtended at the centre, the arc length is nothing but the circumference of circle that is 2$\pi$r where r is circle radius. For an angle of $\theta$, the arc length will be $\frac{\theta }{360}\times 2\pi r$ $=\frac{\theta }{180}\times \pi r$.