Properties of Circles

Front

What is the diameter of a circle?

Back

The diameter is a 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 chord in a circle?

Back

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

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 relationship between the diameter and radius of a circle?

Back

The diameter is twice the length of the radius. (Diameter = 2 × Radius)

Front

How do you find the measure of an angle formed by two chords?

Back

The measure of the angle formed by two chords is equal to half the sum of the measures of the arcs intercepted by the angle.

Front

What is the measure of an inscribed angle?

Back

An inscribed angle is half the measure of the arc it intercepts.

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.

Front

What is the formula for the circumference of a circle?

Back

Circumference = π × Diameter or Circumference = 2 × π × Radius.

Front

What is the area of a circle?

Back

Area = π × Radius².