Circumference

Front

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

Back

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

Front

If the radius of a circle is 9 cm, what is the diameter?

Back

Diameter = 2 × radius = 2 × 9 cm = 18 cm.

Front

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

Back

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

Front

What is π (pi) approximately equal to?

Back

π ≈ 3.14.

Front

If the diameter of a circle is 14 cm, what is the circumference?

Back

Circumference = π × diameter = π × 14 cm ≈ 43.98 cm.

Front

What is the relationship between radius and diameter?

Back

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 24 cm?

Back

Circumference = π × 24 cm ≈ 75.4 cm.

Front

If a circle has a circumference of 37.7 cm, what is its radius?

Back

Radius = Circumference / (2 × π) ≈ 6 cm.

Front

What is the circumference of a circle with a radius of 10 cm?

Back

Circumference = 2 × π × 10 cm ≈ 62.8 cm.