The radius of the circle is 18 cm. Find the length of the arc on which the central angle rests: 1) 120 degrees 2) 35 degrees.

A circle is a set of points on a plane equidistant from a given point. This point is called the center of the circle. The segment connecting the center with any point of the circle is called the radius.

An arc is the portion of a circle between two radii.

The arc length is calculated using the following formula:

L = πrα / 180º, where:

L is the length of the circular arc;

r is the radius of the circle;

α is the central angle;

π – 3.14.

1) L120º = 3.14 · 18 · 120/180 = 6782.4 / 180 = 37.68 cm.

2) L35º = 3.14 ∙ 18 ∙ 35/180 = 1978.2/180 = 10.99 cm.

Answer: the length of the arc on which the central angle of 120º rests is 37.68 cm; the length of the arc on which the central angle of 35º rests is 10.99 cm.