Understanding Circles and Pi

What is the term used for the distance around a circle?

• Perimeter

• Diameter

• Radius

• Circumference

If a circle's diameter is 10 cm, what is its radius?

• 20 cm

• 10 cm

• 5 cm

• 2 cm

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

• Subtract 2

• Add 2

• Multiply by 2

• Divide by 2

If a circle's radius is 12 mm, what is its diameter?

• 24 mm

• 12 mm

• 36 mm

• 6 mm

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

• Subtract 2

• Multiply by 2

• Divide by 2

• Add 2

What is Pi in relation to a circle?

• The radius of a circle

• The diameter of a circle

• The ratio of circumference to diameter

• The area of a circle

What is the approximate value of Pi?

• 2.14

• 4.14

• 3.14

• 5.14

If a circle has a diameter of 8 inches, what is its circumference using Pi?

• 16 inches

• 24 inches

• 25.12 inches

• 31.4 inches

What is the circumference of a circle with a diameter of 6 inches?

• 6 inches

• 12 inches

• 18.84 inches

• 9.42 inches

Which of the following is a consistent result when dividing a circle's circumference by its diameter?

• 2.14

• 5.14

• 3.14

• 4.14