Area and Circumference of a Circle

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, where r is the radius.

Front

What is the radius of a circle?

Back

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

Front

What is the diameter of a circle?

Back

The distance across the circle through the center, equal to 2 times the radius.

Front

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

Back

Area = π × (5)² = 25π ≈ 78.54 square meters.

Front

If the diameter of a circle is 10 meters, what is the circumference?

Back

Circumference = 2 × π × (10/2) = 10π ≈ 31.42 meters.

Front

What is the relationship between radius and diameter?

Back

Diameter = 2 × Radius.

Front

If a circle has a circumference of 31.42 meters, what is the radius?

Back

Radius = Circumference / (2 × π) = 31.42 / (2 × π) ≈ 5 meters.

Front

What is π (pi)?

Back

A mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Front

How do you find the radius if you know the area of a circle?

Back

Radius = √(Area / π).