Circumference Formula Day 1

What is the circumference of the circle? (Use 3.14 for pi.)

What number is pi?

• 1.41

• 2.00

• 3.14

• 5.14

What is the "formal" definition of pi?

• 22/7
• 3.1415926
• the ratio of a circle's circumference to its diameter
• the surface area of a sphere of diameter 22/7

How many digits are in pi?

• 10 trillion
• 5 billion 
• infinite 
• a lot 

What is the circumference?

• 108π

• 18π

• 1088π

• 36π

The radius of the circle is 9 meters.  What is the circle's circumference?

• 9 meters
• 28.26 meters
• 56.52 meters
• 18 meters

If my radius is 10ft, what is my diameter?

• 20ft
• 5ft
• 31.4ft
• 62.8ft

If my radius is 2 yd what is the circumference?

• 4 yd
• 1 yd
• 12.56 yd
• 6.28 yd

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

• C = r²

• C = rd

• A = π·r²

• C = π·d