Secant line point a "tangent line" and in no points an "exterior line". A "chord" of a circle is the line segment that joins two distinct points of the circle. A chord is therefore contained in a unique secant line and each secant line determines a unique chord. In rigorous modern treatments of plane geometry, results that seem obvious and were assumed (without statement) by Euclid in his treatment, are usually proved. For instance, "Theorem (Elementary Circular Continuity)": If formula_1 is a circle and formula_2 a line that contains a point that is inside formula_1 and a point that is outside of
City Circle Line areas of Copenhagen, including the Danish Parliament, the Central Station, City Hall, and multiple stations of the S-train and existing metro stops. Access to the region and commuter heavy rail network is also deliberately provision for at several places along its route; furthermore, a twin-track line is to provide a connection between the City Circle Line and the Nordhavnen Metro. Just as M1 and M2 share a section of the existing metro, the City Circle Line will share a 6-station section with the future M4 line. Initially, two possible routes were considered, after an even bigger screening of ideas. During