Circles & Arcs

Front

What is the center of a circle?

Back

The center of a circle is the point that is equidistant from all points on the circle. It is often denoted as point O.

Front

What is a diameter?

Back

A diameter is a line segment that passes through the center of the circle and has its endpoints on the circle. It is the longest chord of the circle.

Front

What is a radius?

Back

A radius is a line segment from the center of the circle to any point on the circle. It is half the length of the diameter.

Front

What is a chord?

Back

A chord is a line segment whose endpoints lie on the circle. It does not necessarily pass through the center.

Front

What is an arc?

Back

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

Front

What is a sector?

Back

A sector is a region of a circle bounded by two radii and the arc between them.

Front

What is the relationship between the diameter and radius?

Back

The diameter is twice the length of the radius. If r is the radius, then the diameter d is given by d = 2r.

Front

What is the formula for the circumference of a circle?

Back

The circumference C of a circle is given by the formula C = 2πr, where r is the radius.

Front

What is the formula for the area of a circle?

Back

The area A of a circle is given by the formula A = πr², where r is the radius.

Front

What is a semicircle?

Back

A semicircle is half of a circle, formed by a diameter and the arc connecting its endpoints.