When calculating angles using a circle theorem, always state which theorem ... Tangents close tangentA straight line that just touches a point on a curve. A tangent to a circle is perpendicular ...

A tangent is a straight line which touches the circle at a point but does not cut through the circle. There are two theorems involving tangents. The angle between a tangent and a radius is 90°..

Readers of Circles need only be armed with paper, pencil, compass, and straight edge to find great pleasure in following the constructions and theorems. Those who think that geometry using Euclidean ...