Tangents, Radii, and Angles in Circles Review

Front

If a line is tangent to a circle, what is its relationship to the radius at the point of tangency?

Back

The line is perpendicular to the radius at the point of tangency.

Front

What is the measure of a full circle in degrees?

Back

360°

Front

What is the relationship between two tangents drawn from the same external point to a circle?

Back

The two tangents are congruent to each other.

Front

What is the formula for finding the measure of an arc in a circle?

Back

The measure of an arc can be found using the formula: Arc Measure = (Central Angle) x (360°/Full Circle).

Front

What is the measure of a semicircle in degrees?

Back

180°

Front

How do you find the measure of an angle formed by two tangents to a circle from an external point?

Back

The measure of the angle is equal to half the difference of the measures of the intercepted arcs.

Front

What is the relationship between the angles formed by a tangent and a chord through the point of contact?

Back

The angle formed is equal to half the measure of the intercepted arc.

Front

What is the definition of a tangent line to a circle?

Back

A tangent line is a straight line that touches the circle at exactly one point.

Front

What is the relationship between the radius and the tangent line at the point of tangency?

Back

The radius drawn to the point of tangency is perpendicular to the tangent line.

Front

What is the measure of angle ADB if the intercepted arc is 170°?

Back

85° (Angle ADB is half the measure of the intercepted arc).