Consider the ring as shown in the figure below,

The inner radius of ring is ‘r’ and the outer radius is ‘R’.

Area of inner Circle = πr² and Area of outer Circle = πR²

Where r = 12 cm and R = 23 cm

Area of ring = Area of outer circle – Area of inner circle

Area o ring = πR² – πr² (put values of r & R)

⇒ Area of ring = π(23²) – π(12²)

⇒ Area of ring = π(23² – 12²) (taking π common from R.H.S)

⇒ Area of ring = π(529 – 144)

= 1210 cm²

Area of ring is 1210 cm².