The distance from point A to the center of the circle is less than the radius of the circle.

The distance from point A to the center of the circle is less than the radius of the circle. Prove that any line passing through point A is a secant with respect to the given circle.

Draw straight C through point A.

From point O, the center of the circle, we construct the height OH.

Triangle AON is rectangular, then, according to the Pythagorean theorem, OH² = OA² – AH².

OH = √ (OA² – AH²).

By hypothesis, ОА <R, and then ОН <R.

Since OH <R, then the line C intersects the circle at two points, and therefore is a secant, which was required to be proved.



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