The ring is bounded by two circles, the radii of which are equal to 3 cm and 5 cm. What is the S of this ring?

1) in the formula for finding the area of a circle: S = pi * r squared (where pi is a constant number equal to 3.14 (rounded to hundredths), r is the radius of the circle) we substitute 5 centimeters instead of the radius and find the area of the larger circle: S = pi * 5 * 5 = 3.14 * 25 = 78.5 square centimeters;
2) in the formula for finding the area of a circle: S = pi * r in the square, substitute 3 centimeters instead of the radius and find the area of the smaller circle: S = pi * 3 * 3 = 3.14 * 9 = 28.26 square centimeters;
3) 78.5 – 28.26 = 50.24 square centimeters – the area of the ring.
Answer: 50.24 square centimeters.