Circle terms

Front

What is the definition of a circle?

Back

A round closed shape that has no corners where all points of the circle are at an equal distance from the center.

Front

What is the radius of a circle?

Back

The radius (r) is the line segment from the center of the circle to any point on the circle.

Front

How do you find the radius if the diameter is given?

Back

The radius is half of the diameter. If diameter (d) = 8 inches, then radius (r) = d/2 = 4 inches.

Front

What is the diameter of a circle?

Back

The diameter (d) is the line segment that passes through the center of the circle and connects two points on the circle.

Front

If the radius of a circle is 10 ft, what is the diameter?

Back

The diameter is 20 ft, since diameter (d) = 2 * radius (r).

Front

What is the relationship between radius and diameter?

Back

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

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 tangent to a circle?

Back

A tangent 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.

Front

What is the area of a circle?

Back

The area is the space enclosed by the circle, calculated as A = πr^2.