The outer radius and inner diameter of a ring are 5cm, and the area of the ring is () square cm?

The outer radius and inner diameter of a ring are 5cm, and the area of the ring is () square cm?

The outer radius and inner diameter of a ring are 5cm, and the area of the ring is () square cm
The radius of inner circle is 5 / 2 = 2.5
therefore
Area = π * (5 ^ 2-2.5 ^ 2) = 3.14 * 18.75 = 58.875 (cm2)

A ring, the diameter of the outer circle is 30cm, the radius of the inner circle is 5cm. What is the area of the ring
centimeter

Annular area
=3.14×15²-3.14×5²
=628 square centimeters

A ring, the outer radius is 5cm, the inner radius is 3cm. What is its perimeter?

5*5*3.14=78.5
3*3*3.14=28.26
So perimeter = 78.5
Inner circumference = 28.26
What is the question? These two girths have nothing to do with each other