Circumference of a Circle: Practice

Front

What is the formula to calculate the circumference of a circle?

Back

Circumference = 2 × π × r, where r is the radius.

Front

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

Back

Circumference = 2 × π × 7 cm ≈ 43.96 cm.

Front

What does π (pi) represent in circle calculations?

Back

π (pi) is a constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Front

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

Back

Circumference = π × diameter = π × 10 cm ≈ 31.4 cm.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius: Diameter = 2 × radius.

Front

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

Back

Radius = Circumference / (2 × π).

Front

What is the circumference of a circle with a diameter of 12 cm?

Back

Circumference = π × 12 cm ≈ 37.68 cm.

Front

If a circle has a circumference of 62.8 cm, what is its radius?

Back

Radius = Circumference / (2 × π) ≈ 10 cm.

Front

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

Back

Circumference = 2 × π × 5 cm ≈ 31.4 cm.

Front

If the circumference of a circle is 18.84 cm, what is its diameter?

Back

Diameter = Circumference / π ≈ 6 cm.