Circles: Area & Circumference

Front

What is the formula for the circumference of a circle?

Back

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

Front

What is the value of π (Pi) commonly used in calculations?

Back

π (Pi) is approximately 3.14.

Front

How do you calculate the area of a circle?

Back

Area = π × radius².

Front

If a circle has a radius of 10 cm, what is its area?

Back

Area = π × (10 cm)² = 314 cm².

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × radius.

Front

If the diameter of a circle is 12 cm, what is the radius?

Back

Radius = diameter ÷ 2 = 12 cm ÷ 2 = 6 cm.

Front

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

Back

Circumference = 2 × π × 5 inches = 31.4 inches.

Front

How do you find the difference in circumferences of two circles?

Back

Calculate the circumference of each circle and subtract the smaller from the larger.

Front

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

Back

Area = π × (3 m)² = 28.26 m².

Front

If a pizza has a radius of 9.5 inches, what is its area?

Back

Area = π × (9.5 inches)² ≈ 283.53 in².