The radius of a ring is 5cm, the width of the ring is 1cm, and how many square centimeters is the area of the ring?

The radius of a ring is 5cm, the width of the ring is 1cm, and how many square centimeters is the area of the ring?

3.14 × [52 - (5-1) 2], = 3.14 × [25-16], = 3.14 × 9, = 28.26 (square centimeter); a: the area of the ring is 28.26 square centimeter