Circle and Cylinder Flashcard

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 cm, what is the area?

Back

Area = π × (5 cm)² = 78.5 cm² (using π ≈ 3.14).

Front

If the circumference of a circle is 31.4 cm, what is the radius?

Back

Radius = Circumference / (2 × π) = 31.4 cm / (2 × 3.14) = 5 cm.

Front

What is the diameter of a circle with a circumference of 62.8 inches?

Back

Diameter = Circumference / π = 62.8 inches / 3.14 = 20 inches.

Front

What is the area of a circle with a diameter of 10 cm?

Back

Area = π × (5 cm)² = 78.5 cm².

Front

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

Back

Circumference = 2 × π × 7 cm = 43.96 cm.

Front

What is the area of a circle with a radius of 3 cm?

Back

Area = π × (3 cm)² = 28.3 cm².

Front

What is the circumference of a circle with a diameter of 12 inches?

Back

Circumference = π × 12 inches = 37.68 inches.