Question

A circular arc of length 8 ft subtends a central angle of 20°, how do you find the radius of the circle?

Answer 1

If `r` is the radius, then `pi r` is the length of a semicircular arc subtending `180^o = 9 * 20^o`

So `pi r = 9 * 8 "ft" = 72 "ft"`

Divide both sides by `pi` to get: `r = 72/pi "ft"`

Explanation:

`180^o = pi` radians