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
Circle MRT line be operated by SMRT, after the North South line and the East West line. As the name implies, the line is an orbital circle route linking all radial routes leading to the city. It also covers many parts of the Central Area. From Promenade, the line branches into two, with one branch terminating at Dhoby Ghaut, and the other at Marina Bay. The Circle line interchanges with all other Mass Rapid Transit lines within Singapore, such as the North South line and East West line. Plans for the Circle line were laid out in the 1980s, when the then Minister