If the diameter of a nickel is 2.1 cm and the width of each nickel is 0.195 cm, what is the approximate surface area of the roll of nickels? Round your answer to the nearest hundredth. inches squared.

Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?