An Olympic 400 meter track is made up of two straight sides, each measuring 84.39 meters in length, and two semi-circular curves with a radius of 36.5 meters as pictured below
The outer perimeter of the track is equal to :
The sum of the two straightaway sections of the track plus the two semi-circular sections (can be joined to form a circle)
Note: The radius of the outer circle is equal to the inner radius plus the number of lanes multiplied by one meter each