Circumference and Area of Circles

Front

What is the formula for the circumference of a circle?

Back

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

Front

What is the formula for the area of a circle?

Back

Area = π × radius².

Front

If the diameter of a circle is 10 cm, what is the radius?

Back

Radius = diameter / 2 = 10 cm / 2 = 5 cm.

Front

What is the circumference of a circle with a diameter of 40 in?

Back

125.6 in.

Front

What is the area of a circle with a radius of 7 cm?

Back

Area = π × 7² ≈ 153.94 cm².

Front

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

Back

The distance from an edge of a circle to another edge through the center.

Front

What is the circumference of a circle with a diameter of 56 m?

Back

175.8 m.

Front

What is the relationship between diameter and radius?

Back

Radius is half of the diameter.

Front

What is the circumference of a circle with a radius of 3 m?

Back

Circumference = 2 × π × 3 m ≈ 18.85 m.

Front

What is the area of a circle with a diameter of 12 m?

Back

Area = π × (6 m)² ≈ 113.10 m².