Circumference and Area of Circles

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × r, where r is the radius.

Front

What is the value of π (pi) approximately?

Back

π is approximately 3.14.

Front

How do you calculate the area of a circle?

Back

Area = π × r², where r is the radius.

Front

If the radius of a circle is 10 feet, what is its circumference?

Back

Circumference = 2 × π × 10 = 62.8 feet.

Front

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

Back

Area = π × 5² = 78.5 sq. cm.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × radius.

Front

If a circle has a diameter of 20 cm, what is its radius?

Back

Radius = Diameter / 2 = 10 cm.

Front

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

Back

Circumference = π × Diameter = π × 12 ≈ 37.68 inches.

Front

How much area does a circle with a radius of 7 meters cover?

Back

Area = π × 7² ≈ 153.94 sq. meters.

Front

What is the circumference of a circle with a radius of 15 feet?

Back

Circumference = 2 × π × 15 ≈ 94.25 feet.