Parts of a Circle

Front

What is the formula for the area of a circle?

Back

π r²

Front

What is the circumference of a circle?

Back

The distance around the circle, calculated as 2πr or πd.

Front

What is a radius in a circle?

Back

A line segment from the center of the circle to any point on its circumference.

Front

What is a diameter in a circle?

Back

A line segment that passes through the center of the circle and has its endpoints on the circumference; it is twice the length of the radius.

Front

What is a chord in a circle?

Back

A line segment whose endpoints lie on the circumference of the circle.

Front

What is a tangent in relation to a circle?

Back

A line that touches the circle at exactly one point.

Front

What is a sector of a circle?

Back

A region enclosed by two radii and the arc between them.

Front

What is a segment of a circle?

Back

A region enclosed by a chord and the arc connecting its endpoints.

Front

What is the relationship between diameter and radius?

Back

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

Front

What is the circumference of a circle with a radius of 5 cm?

Back

The circumference is 10π cm (C = 2πr).