Circle Vocabulary and Circumference Quiz

What is the relationship between the radius and the diameter of a circle?

• The radius is half the diameter.

• The diameter is half the radius.

• The diameter is twice the radius.

• The radius is twice the diameter.

Which of the following best describes the number pi?

• A whole number used in geometry.

• An irrational number that continues indefinitely without a pattern.

• A fraction used to calculate area.

• A rational number with a repeating pattern.

What is the formula for calculating the circumference of a circle?

• C = 2πr

• C = 2πd

• C = πd

• C = πr²

If the diameter of a circle is 10, what is its circumference using π as 3.14?

• 15.7

• 62.8

• 28.3

• 31.4

In the example where the radius is 5, what is the calculated circumference?

• 10

• 62.8

• 15.7

• 31.4