CONSTRUCTION A -mile track for racing stock cars consists of two semicircles connected by...

CONSTRUCTION A -mile track for racing stock cars consists of two semicircles connected by parallel straightaways (see the figure). In order to provide sufficient room for pit crews, emergency vehicles, and spectator parking, the track must enclose an area of 100,0 square feet. Find the length of the straightaways and the diameter of the semicircles to the nearest foot. [Recall: The area A and circumference C of a circle of diameter d are given by A = πd2/4 and c = πd.]