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
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