Circles: Parts, C & A, Central Angles

Front

What is a circle?

Back

A circle is a set of points in a plane that are equidistant from a fixed point called the 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 measure of a central angle?

Back

A central angle is the angle formed by two radii of a circle, with its vertex at the center of the circle.

Front

What is an arc in a circle?

Back

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

Front

How do you calculate the circumference of a circle?

Back

The circumference (C) can be calculated using the formula C = 2πr, where r is the radius.

Front

How do you calculate the area of a circle?

Back

The area (A) can be calculated using the formula A = πr², where r is the radius.