Circumference of Circles

Front

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

Back

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

Front

What is the value of π (pi) approximately?

Back

π (pi) is approximately 3.14.

Front

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

Back

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

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × radius.

Front

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

Back

Radius = diameter ÷ 2 = 10 ft ÷ 2 = 5 ft.

Front

What is the circumference of a circle with a diameter of 1 meter?

Back

Circumference = π × 1 m ≈ 3.14 m.

Front

How do you convert radius to diameter?

Back

Multiply the radius by 2.

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 15 inches?

Back

Circumference = 2 × π × 15 inches ≈ 94.2 inches.

Front

If the radius is doubled, how does the circumference change?

Back

The circumference also doubles.