Give numerical values for order-of-magnitude estimates for the following quantities. Explain and justify the reasonableness of the assumptions and approximations that you need to make.

(a) The number of cars that pass through an intersection of two busy streets during the evening commute on a typical workday

(b) The number of bricks that form the exterior of a large building on a university campus

(c) The volume of concrete in the sidewalks on a university campus