Tangent is defined as which of the following?

Tangent is defined as which of the following?

• A. A line that intersects a circle at two points.
• B. A line that passes through the center of a circle.
• C. A line parallel to the radius.
• D. A straight or curved line that intersects a circle or arc at one point only.

Answer: (D)

Tangency means a line (or in some contexts a curve) just touches the circle at exactly one point, without crossing through it. For a circle, a tangent is a straight line that meets the circle in one point, and at that point the radius to that point is perpendicular to the tangent. This single-point contact is what sets a tangent apart from other lines: a line that hits the circle in two points is a secant, and a line that passes through the center is a diameter, not a tangent. The statement that a line touches the circle at exactly one point captures the essential idea of tangency.

Tangency means a line (or in some contexts a curve) just touches the circle at exactly one point, without crossing through it. For a circle, a tangent is a straight line that meets the circle in one point, and at that point the radius to that point is perpendicular to the tangent. This single-point contact is what sets a tangent apart from other lines: a line that hits the circle in two points is a secant, and a line that passes through the center is a diameter, not a tangent. The statement that a line touches the circle at exactly one point captures the essential idea of tangency.