Circumference Challenge

What is the formula to calculate the circumference of a circle?

• π * r

• r^2

• 2 * r

• 2 * π * r

If the diameter of a circle is 10 cm, what is its circumference?

• 25.12 cm

• 20.5 cm

• 31.42 cm

• 15.7 cm

What is the circumference of a circle with a radius of 5 cm?

• 25.1327 cm

• 15.70795 cm

• 31.4159 cm

• 20.123 cm

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

• 10 cm

• 15 cm

• 20 cm

• 25 cm

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

• Circumference = π x Diameter

• Circumference = Diameter^2

• Circumference = 2 x Diameter

• Circumference = Diameter + π

How is the circumference of a circle related to its radius?

• C = πr^2

• C = 2πr

• C = 2r

• C = r^2

If the circumference of a circle is doubled, how does it affect the radius?

• The radius is squared.

• The radius is tripled.

• The radius remains the same.

• The radius is halved.

What units are commonly used to measure circumference?

• grams

• inches

• yards

• inches, feet, meters, centimeters, kilometers

What is the approximate value of pi (π) used in circumference calculations?

• 4.20

• 2.71

• 3.00

• 3.14

Explain how to find the circumference of a circle using the radius.

• Circumference = 2 * radius

• Circumference = 2 * π * radius

• Circumference = π * radius

• Circumference = π * radius^2