Secant line 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 interval on a secant whose endpoints are these points. A straight line can intersect a circle in two, one or zero points. A line intersecting in two points is called a "secant line", in one
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