The chord of the circle is 9 m. It contracts the arc at 60, find the length of the arc.

Let’s draw the radii of the circle OB and OA, then the triangle AOB is isosceles. Since the chord AB contracts the arc at 60, the central angle resting on this chord is also 60. Then the triangle AOB is isosceles and one of the angles is 600, which means this triangle is equilateral OA = OB = AB = R = 9 cm.

Let us determine the length of the arc AB.

L = n * R * α / 180, where α is the arc angle in degrees.

L = n * 9 * 60/180 = 3 * n cm.

Answer: The length of the arc is 3 * n cm.