Radius, Diameter, Circumference

Front

What is the radius of a circle?

Back

The measurement from the center of a circle to an edge of the circle.

Front

What does 'circumference' mean?

Back

Distance around a circle.

Front

How do you calculate the circumference of a circle?

Back

Circumference = 2 × π × radius.

Front

What is the diameter of a circle?

Back

The measurement from one edge of the circle to the other edge through the center.

Front

How do you find the diameter if you know the radius?

Back

Diameter = 2 × radius.

Front

If a circle has a radius of 5 cm, what is its diameter?

Back

10 cm.

Front

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

Back

10 cm.

Front

What is the formula to find the radius from the circumference?

Back

Radius = Circumference / (2 × π).

Front

If the circumference of a circle is 31.4 cm, what is the radius?

Back

5 cm.

Front

What is π (pi)?

Back

A constant approximately equal to 3.14, used in calculations involving circles.