Circumference of Circles and Perimeter of Composite Shapes

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 12.5 mm, what is its circumference?

Back

78.54 mm (using π ≈ 3.14).

Front

What is the diameter of a circle if the radius is 10 in?

Back

Diameter = 2 × radius = 20 in.

Front

How do you find the radius if you know the circumference of a circle?

Back

Radius = Circumference / (2 × π).

Front

What is the circumference of a circle with a diameter of 3.5 feet?

Back

10.99 ft (using π ≈ 3.14).

Front

What is the circumference of a circle with a radius of 54 m?

Back

339.12 m (using π ≈ 3.14).

Front

If a circular garden has a circumference of 393 ft, what is the radius?

Back

Radius = Circumference / (2 × π) = 62.5 ft.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × radius.

Front

What is the perimeter of a composite shape?

Back

The perimeter is the total distance around the shape, calculated by adding the lengths of all sides.

Front

How do you calculate the perimeter of a rectangle?

Back

Perimeter = 2 × (length + width).