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
Power of a point centered on the midpoint of O and P and passing through both points. It can also be shown that the point Q is the inverse of P with respect to the given circle. The "power of a point theorem", due to Jakob Steiner, states that for any line through "A" intersecting a circle "c" in points "P" and "Q", the power of the point with respect to the circle "c" is given up to a sign by the product of the lengths of the segments from "A" to "P" and "A" to "Q", with a positive sign if "A" is