In previous posts we talked about inscribed angle. The segment angle is defined as the angle formed between a chord of a circle and the tangent to the circle at one of the ends of the chord. This angle can be seen as a special case of the inscribed angle, where the vertex of the angle is precisely on one of the points that define the arc. To understand better, imagine a circle with a rope extended from one point to another. At one of the points where the rope touches the circle, draw a tangent line. The angle formed between this tangent and the chord is what we call the segment angle. An interesting property of this angle is that it is half the measure of the central angle that subtends the same arc.