Find the length of an arc of a circle; radius of a circle is 3 cm; the degree measure of this arc is 120.

The part of a circle is called an arc. The arc length of n degrees is found by the formula p = πrn / 180,
where p is the length of the arc, r is the radius of the circle, n is the angle of the corresponding arc.
We substitute the corresponding values r = 3 cm., N = 120 ° into the formula, then
p = πrn / 180 = (π * 3 * 120) / 180 = 2π (see) or p = 2π = 2 * 3.14≈6.28 (see),
where π≈3.14.
Answer: 2π cm or 6.28 cm