Answer: 423.11 m^2
Step by step explanation:
Area of a circle formula pi*r^2
First solve the area of the big circle
3.14*21^2=1384.74 m^2
Now find the are of the smaller circle
r=21-3.5=17.5
3.14*(17.5)^2=961.63 m^2
Now we can minus the small area off the big area to get the shaded area.
1384.74-961.63=423.11 m^2
So the area of the shaded region is 423.11 m^2