The outer and inner radii of the circular ring are equal: R1 = 12 R2 = 5. A piece is cut out of it with radii making

The outer and inner radii of the circular ring are equal: R1 = 12 R2 = 5. A piece is cut out of it with radii making an angle of 18 (degrees). Find the area of the cut part.

Determine the area of a circle with a diameter of 12 cm.

S1 = n * R1 ^ 2 = 144 * π cm2.

Determine the area of a circle with a diameter of 5 cm.

S2 = n * R2 ^ 2 = 25 * n cm2.

Then the area of the ring is: Skol = S1 – S2 = 144 * n – 25 * n = 119 * n cm2.

Let’s calculate what part 180 is from the degree measure of the circle. 18/360 = 1/20.

Then the area of the cut out piece is: S = Skol / 20 = 119 * n / 20 = 5.95 * n cm2.

Answer: The area of the embedded part is 5.95 * n cm2.