Parts of a Circle

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through its center, equal to twice the radius.

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 circumference of a circle?

Back

The circumference is the distance around the circle, calculated as C = πd or C = 2πr.

Front

What is the center of a circle?

Back

The center is the point that is equidistant from all points on the circumference.

Front

What is a chord in a circle?

Back

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

Front

How do you calculate the diameter if you know the radius?

Back

Diameter = 2 × Radius.

Front

How do you calculate the radius if you know the diameter?

Back

Radius = Diameter ÷ 2.

Front

What is the relationship between diameter and circumference?

Back

The circumference is π times the diameter (C = πd).

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius.

Front

What is a semicircle?

Back

A semicircle is half of a circle, formed by cutting a whole circle along its diameter.