Area and Circumference

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 7 cm, what is the area?

Back

Area = π × (7 cm)² ≈ 153.94 cm².

Front

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

Back

Radius = Diameter / 2 = 10 m / 2 = 5 m.

Front

What is the relationship between radius and diameter?

Back

The radius is half the diameter.

Front

What is the area of a circle with a radius of 5 inches?

Back

Area = π × (5 in)² ≈ 78.54 in².

Front

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

Back

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

Front

If the area of a circle is 50 cm², what is the radius?

Back

Radius = √(Area / π) ≈ 3.99 cm.

Front

What is the diameter of a circle with an area of 28.26 cm²?

Back

Diameter = 2 × √(Area / π) ≈ 6 cm.

Front

What is π (pi)?

Back

π (pi) is a constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.