Circles and Pi

What is the value of π (pi) rounded to two decimal places?

• 2.14

• 3.14

• 3.41

• 2.31

Fill in the blank: The circumference of a circle is always ______ times its diameter.

Which of the following best describes π?

• The ratio of the area of a circle to its radius

• The ratio of the circumference of a circle to its diameter

• The ratio of the diameter to the radius

• The ratio of the radius to the circumference

If a circle has a diameter of 10 cm, what is its circumference? (Use π ≈ 3.14)

Select the correct formula for the circumference (C) of a circle with diameter (d).

• C = 2πd

• C = πd

• C = πr^2

• C = 2d

A circle has a circumference of 18.84 cm. What is its diameter? (Use π ≈ 3.14)

• 6 cm

• 3 cm

• 12 cm

• 9 cm

Drop down: π is a (choose one) ______ number.

• rational

• irrational

If the diameter of a circle is doubled, what happens to the circumference?

• It stays the same

• It is halved

• It is doubled

• It is tripled

Fill in the blank: The ratio circumference/diameter of any circle is always ______.

Which of the following is closest to the value of π?

• 3.14159

• 2.71828

• 1.61803

• 1.41421