Circles

Front

What is a circle?

Back

A circle is a shape consisting of all points in a plane that are at a given distance (radius) from a fixed point (center).

Front

What is the radius of a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through the center, equal to twice the radius.

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle, calculated as C = 2πr, where r is the radius.

Front

What is the area of a circle?

Back

The area is the space contained within the circle, calculated as A = πr², where r is the radius.

Front

What is a chord in a circle?

Back

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

Front

What is a tangent to a circle?

Back

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

Front

What is an arc in a circle?

Back

An arc is a portion of the circumference of a circle.

Front

What is a sector of a circle?

Back

A sector is a region enclosed by two radii and the arc between them.

Front

What is the central angle of a circle?

Back

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