Radius, Diameter, and Circumference

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

How do you calculate the diameter from the radius?

Back

Multiply the radius by 2.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 × π × radius.

Front

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

Back

10 cm.

Front

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

Back

5 cm (using the formula C = 2πr).

Front

What is π (pi)?

Back

π is 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 circumference if you know the diameter?

Back

Multiply the diameter by π (C = π × diameter).

Front

What is the diameter of a circle with a radius of 7 m?

Back

14 m.

Front

If a circle has a circumference of 62.8 m, what is its diameter?

Back

20 m (using the formula C = π × diameter).