Geometry: Chapter 9 Review of 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 from a fixed point, called the center.

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 radius?

Back

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

Front

What is a diameter?

Back

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

Front

What is a chord?

Back

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

Front

What is a tangent?

Back

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

Front

What is a secant?

Back

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

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.