Circles Vocab, Radius, & Diameter

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

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle.

Front

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

Back

20 cm

Front

If the diameter of a circle is 16 cm, what is the radius?

Back

8 cm

Front

What is the formula for the circumference of a circle?

Back

Circumference = π × diameter or Circumference = 2 × π × radius.

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, used in calculations involving circles.

Front

How do you find the radius if you know the circumference?

Back

Radius = Circumference / (2 × π).

Front

What is a chord in a circle?

Back

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

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the length of the radius.