Circumference of a Circle

Front

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

Back

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

Front

What does the term 'radius' refer to in a circle?

Back

The radius is the distance from the center of the circle to any point on its edge.

Front

How do you calculate the diameter of a circle if you know the radius?

Back

Multiply the radius by 2.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius.

Front

If the radius of a circle is 5 cm, what is the circumference? (Use π ≈ 3.14)

Back

Circumference = 2 × π × 5 = 31.4 cm.

Front

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

Back

Diameter = 2 × radius = 2 × 10 cm = 20 cm.

Front

What is the circumference of a circle with a diameter of 8 cm? (Use π ≈ 3.14)

Back

Circumference = π × diameter = 3.14 × 8 = 25.12 cm.

Front

What is the radius of a circle with a circumference of 31.4 cm? (Use π ≈ 3.14)

Back

Radius = Circumference / (2 × π) = 31.4 / (2 × 3.14) = 5 cm.

Front

What is the term for the distance around a circle?

Back

Circumference.

Front

If a circle has a circumference of 62.8 cm, what is its diameter? (Use π ≈ 3.14)

Back

Diameter = Circumference / π = 62.8 / 3.14 = 20 cm.