A triangle inside a circle represents the Sobriety Circle and Triangle Symbol used by the Alcoholics Anonymous group. The equilateral triangle represents unity, recovery and service in response to the physical, mental and spiritual parts of the disease of alcoholism. Here you'll learn how to calculate angles formed outside a circle by tangent and secant lines. This video gives more detail about the mathematical principles presented in Angles Outside a Circle.
Circumscribed circle, C, and circumcenter, O, of a cyclic polygon, PIn, the circumscribed circle or circumcircle of a is a that passes through all the of the polygon. The of this circle is called the circumcenter and its radius is called the circumradius.A polygon that has a circumscribed circle is called a cyclic polygon (sometimes a concyclic polygon, because the vertices are ). All, all, all and all are cyclic.A related notion is the one of a, which is the smallest circle that completely contains the polygon within it. Not every polygon has a circumscribed circle, as the vertices of a polygon do not need to all lie on a circle, but every polygon has a unique minimum bounding circle, which may be constructed by a algorithm.
Even if a polygon has a circumscribed circle, it may not coincide with its minimum bounding circle; for example, for an, the minimum bounding circle has the longest side as diameter and does not pass through the opposite vertex. Of the circumcircle (red) and the circumcenter Q (red dot)The circumcenter of a triangle can be by drawing any two of the three. For three non-collinear points,these two lines cannot be parallel, and the circumcenter is the point where they cross.
Any point on the bisector is equidistant from the two points that it bisects, from which it follows that this point, on both bisectors, is equidistant from all three triangle vertices.The circumradius is the distance from it to any of the three vertices.