Tangents, Chords, Arc Measure, Inscribed and Central Angles

Front

What is a tangent to a circle?

Back

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

Front

Define a chord in a circle.

Back

A chord is a line segment whose endpoints lie on the circle.

Front

What is the measure of a central angle?

Back

A central angle is the angle whose vertex is at the center of the circle and whose sides are radii.

Front

How is the measure of an inscribed angle related to the arc it intercepts?

Back

The measure of an inscribed angle is half the measure of the intercepted arc.

Front

What is the relationship between the angles formed by two intersecting chords?

Back

The measure of the angle formed by two intersecting chords is equal to the average of the measures of the arcs intercepted by the angle and its vertical angle.

Front

If two tangents are drawn from a point outside a circle, what can be said about their lengths?

Back

The lengths of the two tangents from a point outside the circle to the points of tangency are equal.

Front

What is the formula for the measure of an arc?

Back

The measure of an arc is equal to the measure of the central angle that intercepts it.

Front

How do you find the radius of a circle if you know the length of a chord and the distance from the center to the chord?

Back

Use the formula: r = √(d² + (c/2)²), where r is the radius, d is the distance from the center to the chord, and c is the length of the chord.

Front

What is the relationship between the measures of arcs AB and AC if they are intercepted by angles at the center of the circle?

Back

The measure of arc AB is equal to the measure of the central angle that intercepts it.

Front

If the measure of arc SR is 65°, what is the measure of the inscribed angle that intercepts arc SR?

Back

The measure of the inscribed angle is 32.5°.