Area and Circumference of a Circle

Front

What is the distance around a circle?

Back

Circumference

Front

What is the formula to calculate the circumference of a circle?

Back

C = πd or C = 2πr, where d is the diameter and r is the radius.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through its center, equal to twice the radius.

Front

What is the radius of a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.

Front

What is the formula to calculate the area of a circle?

Back

A = πr², where r is the radius.

Front

If a circle has a radius of 5 inches, what is its area?

Back

A = π(5)² = 78.54 square inches.

Front

If a circle has a diameter of 10 feet, what is its circumference?

Back

C = π(10) = 31.42 feet.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the radius (d = 2r).

Front

What is the approximate value of π (pi)?

Back

π is approximately 3.14.

Front

If a circle has a circumference of 62.83 inches, what is its radius?

Back

r = C/(2π) = 62.83/(2π) = 10 inches.