Circumference and Area

Front

What is the formula for the area of a circle?

Back

Area = π × r², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × r or Circumference = π × d, where d is the diameter.

Front

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

Back

Diameter = 2 × radius = 20 cm.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius.

Front

How do you calculate the area of a circle with a radius of 7 cm?

Back

Area = π × (7 cm)² ≈ 153.94 cm².

Front

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

Back

Circumference = 2 × π × 5 m ≈ 31.42 m.

Front

If the diameter of a circle is 30 inches, what is the radius?

Back

Radius = Diameter / 2 = 15 inches.

Front

What is the area of a circle with a diameter of 8 m?

Back

Area = π × (4 m)² ≈ 50.27 m².

Front

What does the term 'circumference' refer to?

Back

Circumference is the distance around the circle.

Front

What is the area of a circle with a radius of 12.5 meters?

Back

Area = π × (12.5 m)² ≈ 490.87 m².