This was the federal government's first entry into transportation.
a. baltimore and ohio railroad
c. u. s. airways
b. national road
d. ford motor car company

The Federal Government's first entry into transportation was National Road (b). The Federal Government was concerned with the speed at which goods were transported from their source to their destination. Goods were primarily transported overland by horse and rider. They were transported along the waterways by ships and sail boats. The first road that the government funded was the Boston Post Road. It was built to increase the speed of the delivery of mail. The Boston Post Road was constructed between New York City and Boston. 

The answer is forindependence.

Use the formula: (n-2)×180, where n is the number of sides(18-2)×180= 28800, now this is the full exterior angle of 18-gon so you divide it by 18.28800÷18=160