Circumference of a circle

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 relationship between radius and diameter?

Back

Diameter is twice the radius. (Diameter = 2 × radius)

Front

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

Back

10 cm.

Front

What is π (pi)?

Back

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

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 radius of 7 cm?

Back

Circumference = 2 × π × 7 cm ≈ 43.98 cm.

Front

If the diameter of a circle is 12 inches, what is the circumference?

Back

Circumference = π × 12 inches ≈ 37.68 inches.

Front

What is the circumference of a circle with a diameter of 10 m?

Back

Circumference = π × 10 m ≈ 31.4 m.

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 penny with a radius of 9.5 mm?

Back

Circumference = 2 × π × 9.5 mm ≈ 59.66 mm.