angles in circles

Front

What is a central angle in a circle?

Back

A central angle is an angle whose vertex is at the center of the circle and whose sides are radii that extend to the circumference.

Front

What is an inscribed angle?

Back

An inscribed angle is an angle formed by two chords in a circle which have a common endpoint. The vertex of the angle is on the circle.

Front

What is the relationship between a central angle and an inscribed angle that subtend the same arc?

Back

The measure of a central angle is twice the measure of the inscribed angle that subtends the same arc.

Front

Write the general equation of a circle with center (h, k) and radius r.

Back

(x - h)² + (y - k)² = r².

Front

If the radius of a circle is 5, what is the equation of the circle centered at the origin?

Back

x² + y² = 25.

Front

What is the measure of an angle formed by two tangents drawn from a point outside the circle?

Back

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

Front

What is the angle formed by a tangent and a chord through the point of contact?

Back

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

Front

If two chords intersect inside a circle, how do you find the measure of the angles formed?

Back

The measure of each angle is equal to half the sum of the measures of the arcs intercepted by the angle and its vertical angle.

Front

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

Back

The product of the lengths of the segments of one chord is equal to the product of the lengths of the segments of the other chord.

Front

What is a diameter of a circle?

Back

A diameter is a chord that passes through the center of the circle and is the longest chord.