Area and Circumference Flashcard

Front

What is the formula for the area of a circle?

Back

A = πr², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

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

Front

If a circle has a radius of 4 feet, what is its circumference?

Back

C = 2π(4) = 8π ≈ 25.12 feet.

Front

If a circle has a diameter of 10 inches, what is its area?

Back

A = π(5)² = 25π ≈ 78.54 square inches.

Front

What does 'diameter' mean?

Back

The distance across a circle through its center.

Front

What does 'radius' mean?

Back

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

Front

What is the relationship between diameter and radius?

Back

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

Front

How do you find the circumference of a circle using the diameter?

Back

C = πd.

Front

What is the approximate value of π?

Back

π ≈ 3.14.

Front

If a circular garden has a radius of 6 meters, what is its area?

Back

A = π(6)² = 36π ≈ 113.1 square meters.