Yellow Circles, Circumference, Perimeter

Front

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

Back

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

Front

If the diameter of a circle is 21 feet, what is the radius?

Back

Radius = diameter / 2 = 21 ft / 2 = 10.5 ft.

Front

What is the relationship between diameter and radius?

Back

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

Front

How do you find the diameter if you know the radius?

Back

Diameter = 2 × Radius.

Front

What is the circumference of a circle with a radius of 2 yards?

Back

Circumference = 2 × π × 2 yd = 12.56 yd.

Front

What is the radius of a circle with a circumference of 31.4 feet?

Back

Radius = Circumference / (2 × π) = 31.4 ft / (2 × π) ≈ 5 ft.

Front

What does the term 'perimeter' refer to in geometry?

Back

Perimeter is the total distance around a two-dimensional shape.

Front

How do you calculate the perimeter of a circle?

Back

The perimeter of a circle is the same as its circumference.

Front

If a penny has a radius of 9.5 mm, what is its diameter?

Back

Diameter = 2 × Radius = 2 × 9.5 mm = 19 mm.

Front

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

Back

Circumference = π × diameter = π × 10 ft ≈ 31.42 ft.