Circles: area and circumference

Front

What is a circle?

Back

A circle is a round shape where every point is the same distance from the center.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle, passing through the center.

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 edge.

Front

How do you find the circumference of a circle?

Back

Circumference = π × diameter.

Front

What is π (pi)?

Back

π is the ratio of the circumference of any circle to its diameter, approximately 3.14.

Front

What is the formula for the area of a circle?

Back

Area = π × radius².

Front

If the diameter of a circle is 2cm, what is the radius?

Back

The radius is 1cm.

Front

What is the circumference of a circle with a diameter of 2cm?

Back

6.28cm.

Front

What is the area of a circle with a diameter of 2cm?

Back

3.14cm².

Front

If the radius of a pizza is 9 ½ in, what is its area?

Back

Approximately 283 ½ in².