CIRCLES FLASHCARD

Front

What is an inscribed angle in a circle?

Back

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

Front

What is the formula for the area of a sector of a circle?

Back

Area of a sector = (θ/360) × πr², where θ is the central angle in degrees and r is the radius.

Front

What is a tangent line to a circle?

Back

A tangent line is a straight line that touches the circle at exactly one point. It is perpendicular to the radius drawn to the point of contact.

Front

What does it mean for arcs to be congruent?

Back

Congruent arcs are arcs that have the same measure and are subtended by congruent chords.

Front

What is the relationship between congruent chords and their corresponding arcs?

Back

Congruent chords in a circle subtend congruent arcs, meaning they have the same length and measure.

Front

How do you find the measure of an inscribed angle?

Back

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

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

How do you calculate the length of an arc?

Back

Length of an arc = (θ/360) × 2πr, where θ is the central angle in degrees and r is the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2πr, where r is the radius of the circle.

Front

What is the central angle of 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 circle.