What angle do a tangent and a radius form at their intersection?

When a tangent to a circle intersects with a radius drawn to the point of tangency, the angle formed between them is a right angle, which measures 90 degrees. This is a fundamental property of circles in Euclidean geometry. The tangent line touches the circle at exactly one point, and at that point, the radius is perpendicular to the tangent. This relationship holds true for any circle, reinforcing the idea that the tangent is "straight out" from the point of tangency while the radius points directly into the circle. Thus, the correct answer is that the angle formed is a right angle.