Find the area of the large circle and the small circle and then subtract those two to find the area of the shaded region.
Radius of the large circle = 5.25
Radius of the small circle = 2.25
Area of larger circle =
πr² = (3.14)(5.25)² = 86.55
Area of smaller circle =
πr² = (3.14)(2.25)² = 15.91
Now subtract the two areas:
86.55 - 15.91 = 70.64
The area of the shaded region is approx. 70.7 cm²
Hope this helps :)