Properties of Circles

Front

What is a circle?

Back

A circle is a shape consisting of all points in a plane that are a fixed distance (radius) from a central 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 a line segment that passes through the center of the circle and has its endpoints on the circle. It is twice the length of the radius.

Front

What is a chord in a circle?

Back

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

Front

What is a secant line?

Back

A secant line is a line that intersects a circle at two points.

Front

What is a tangent line?

Back

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

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 enclosed by the circle, calculated as A = πr², where r is the radius.

Front

What is the relationship between the radius and diameter?

Back

The diameter is twice the length of the radius (d = 2r).

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.