11.2: Arcs & Chords

Front

What is an arc in a circle?

Back

An arc is a portion of the circumference of a circle, defined by two endpoints on the circle.

Front

What is a chord in a circle?

Back

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

Front

How do you calculate the measure of an arc?

Back

The measure of an arc can be calculated using the central angle that subtends the arc, measured in degrees.

Front

What is the relationship between the radius and the arc length?

Back

The arc length is directly proportional to the radius of the circle and the measure of the central angle.

Front

What is the formula for the length of an arc?

Back

Arc length = (θ/360) * 2πr, where θ is the central angle in degrees and r is the radius.

Front

What is the measure of a semicircle?

Back

The measure of a semicircle is 180 degrees.

Front

If the radius of a circle is 70, what is the circumference?

Back

Circumference = 2πr = 2π(70) ≈ 439.82.

Front

What is the relationship between arcs and chords?

Back

Equal arcs subtend equal chords, and equal chords subtend equal arcs.

Front

How do you find the radius if you know the arc length and angle?

Back

Rearrange the arc length formula: r = (arc length * 360) / (2πθ).

Front

What is the central angle of an arc?

Back

The central angle is the angle whose vertex is at the center of the circle and whose sides intersect the endpoints of the arc.