Question

Under which condition can a secant to a circle be called a tangent?

• A. The points of intersection are infinite distance apart.
• B. The secant passes through the centre of the circle.
• C. The points of intersection are coincident.
• D. The secant is a curved line.

Answer 1

The correct option is C

The points of intersection are coincident.

Consider a line l which is a secant to a circle with centre O. Let PQ be the points of intersection. If we rotate the secant anticlockwise about the point P, then Q comes closer and closer to the point P and finally the position of Q coincides with P and the secant becomes a tangent at point P.