Fundamentals of Surveying (FS) Practice Exam

The radius of a circle is ______ to a tangent at the point of tangency.

1. parallel

2. perpendicular

3. tangential

4. congruent

The correct answer is: perpendicular

At the point of tangency, the radius of a circle is always perpendicular to the tangent line. This geometric principle is derived from the definition of a tangent, which is a line that touches the circle at exactly one point. Since a radius connects the center of the circle to any point on its circumference, at the point where the tangent touches the circle, this radius forms a right angle with the tangent line. Thus, in the scenario given, the correct concept regarding the relationship between a radius and the tangent at the point of tangency is that they intersect at a right angle, making them perpendicular to each other.