Tangent Conjectures


A tangent line to a circle is any line which intersects the circle in exactly one point. You can think of a tangent line as "just touching" the circle, without ever traveling "inside". A line which intersects a circle in two points is called a secant line. Chords of a circle will lie on secant lines.

The precise statement of the conjecture is:

Conjecture (Tangent Conjecture I ): Any tangent line to a circle is perpendicular to the radius drawn to the point of tangency.

Conjecture (Tangent Conjecture II ): Tangent segments to a circle from a point outside the circle are equal in length.

Interactive Sketch Pad Demonstration:

Linked Activity:

Please feel free to try the activity sheet associated with this conjecture.

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