The radius of the outer circle of a ring is 7cm, and the radius of the inner circle is 5cm?

The radius of the outer circle of a ring is 7cm, and the radius of the inner circle is 5cm?

Area 3.14 × (7 × 7-5 × 5)
=3.14×24
=75.36 square centimeter
Perimeter 3.14 × (7 + 5) × 2
=3.14×24
=36 cm