see the picture attached to better understand the problem
we know that
area of a circle=pi*r²
area of the larger circle
r= 11 units
Area=pi*11²-----> 379.94 units ²
area of smaller circle
area=pi*9²-----> 254.34 units²
area of the shaded region=area larger circle-area smaller circle
so
area of the shaded region=379.94-254.34-----> 125.60 units²
the answer is
125.60 units²