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
Circle by three points formula_10 not on a line is obtained by a conversion of the "3-point-form of a circle's equation" Homogeneous form<br> In homogeneous coordinates, each conic section with the equation of a circle has the form It can be proven that a conic section is a circle exactly when it contains (when extended to the complex projective plane) the points "I"(1: "i": 0) and "J"(1: −"i": 0). These points are called the circular points at infinity. In polar coordinates, the equation of a circle is: where "a" is the radius of the circle, formula_14 is the polar coordinate of