Answer:
Answer = 3.14 * 40 = 125.6m^2
Step-by-step explanation:
Let R be the greater radius and r be the smaller radius
A) Area of the sidewalk = \pi R^2 - \pi r^2 - This can be the expression
B) pi = 3.14
= pi (R^2-r^2)
= pi (11^2-9^2)
= pi (121-81)
= pi *40
That was the simplified expression
Answer = 3.14 * 40 = 125.6m^2
