Answer:
(a) 
(b) 
Step-by-step explanation:
(a) Write and simplify an expression for the exact area of the sidewalk.
(b) Find the approximate area of the sidewalk. Use 3.14 to approximate .
(a) The sidewalk area is the difference in the area of outer circle and inner circle.
Use formula
for the area of the circle:

The difference is

(b) Use approximation
then

<span>5/8 = 2m + 3/8
Subtract 3/8 from 5/8
2/8=2m
Divide 2 on both sides
Final Answer: 2/16 or 1/8 *Both answers are equivalent to each other.</span>
2/3 × 42 = 28 × = 280 is ur answer