Radius, Diameter, Circumference Review

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

How do you calculate the circumference of a circle?

Back

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

Front

If the radius of a circle is 7 cm, what is the diameter?

Back

The diameter is 14 cm (diameter = 2 × radius).

Front

If the diameter of a circle is 10 m, what is the circumference?

Back

Circumference = π × 10 m ≈ 31.42 m.

Front

What does 'circumference' mean?

Back

Circumference is the distance around a circle.

Front

If the radius of a circle is 5 inches, what is the circumference?

Back

Circumference = 2 × π × 5 in ≈ 31.42 in.

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the radius.

Front

If a circle has a circumference of 62.83 cm, what is its diameter?

Back

Diameter = Circumference / π ≈ 20 cm.

Front

What is the formula for finding the radius if you know the circumference?

Back

Radius = Circumference / (2 × π).