Secant line 3-secants of a finite set of points. Finiteness of the set of points is not essential in this definition, as long as each line can intersect the set in only a finite number of points. Secant line In geometry, a secant of a curve is a line that intersects the curve in at least two (distinct) points. The word "secant" comes from the Latin word "secare", meaning "to cut". In the case of a circle, a secant will intersect the circle in exactly two points and a chord is the line segment determined by these two points, that is the
Dividing a circle into areas where two of the old lines intersect. For each "O" and "I", the line "OI" crosses the circle in one point other than "O". Since the circle has infinitely many points, it has a point "A" which will be on none of the lines "OI". Then, for this point "A" and all of the old points "O", case "b" will be true. This lemma means that, if there are "k" lines crossing "AO", then each of them crosses "AO" at a different point and "k+1" new areas are created by the line "AO". The lemma establishes an important property for