Circles: Area & 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

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius.

Front

If the radius of a circle is 5 m, what is the area?

Back

Area = π × (5 m)² = 78.5 m² (using π ≈ 3.14).

Front

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

Back

Circumference = π × 10 m = 31.4 m (using π ≈ 3.14).

Front

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

Back

Diameter = 2 × 7 cm = 14 cm.

Front

What is the circumference of a circle with a radius of 3.5 ft?

Back

Circumference = 2 × π × 3.5 ft = 21.99 ft (using π ≈ 3.14).

Front

What is the area of a circle with a radius of 4 m?

Back

Area = π × (4 m)² = 50.24 m² (using π ≈ 3.14).

Front

What is the circumference of a quarter with a diameter of 24.26 mm?

Back

Circumference = π × 24.26 mm ≈ 76.18 mm (using π ≈ 3.14).

Front

What is the radius of a circle with a diameter of 16 m?

Back

Radius = Diameter / 2 = 16 m / 2 = 8 m.