Question

What is the radius of a circle with a central angle of 4π/7 radians that intercepts an arc of length 12π inches?

Answer 1

21 inches

Explanation:

If
`\alpha` is the central angle, then the length of the arc on which this angle subtends is

`l=r\cdot \alpha.`

Hence,

`12\pi =(4\pi)/(7)\cdot r,\\ \\r=(12\pi)/((4\pi)/(7))=(12\pi)/(1)\cdot (7)/(4\pi)=21\ in.`