Question

Two circles of radius r are tangent to each other. Two lines pass through the centre of one circle and are tangent to the other circle at points A and B as shown in the diagram. Find an expression for the distance between A and B.

Answer 1

Answer:

In Euclidean plane geometry, a tangent line to a circle is a line that touches the circle at exactly one point, never entering the circle's interior. Tangent lines to circles form the subject of several theorems, and play an important role in many geometrical constructions and proofs. Since the tangent line to a circle at a point P is perpendicular to the radius to that point, theorems involving tangent lines often involve radial lines and orthogonal circles.