7 - Circumference Practice

There are 2 fomulas for the circumfernce of a circle, one is:

• $C=2\pi d$

• $C=\pi d$

• $C=\pi r^2$

What is the correct set up to find the circumference of the circle?

• $C\ =\ \pi\ \left(20\right)$

• $C\ =\ 2\pi\left(20\right)$

• $C\ =\ 2\pi\left(10\right)^2$

What is the circumference of the circle?

Pi button, rounded to nearest whole #

• 44

• 22

• 88

What is the are the circumference of a circle with a radius of 12 cm?

PI button, nearest hundredths

• 452.39

• 114.14

• 75.40

What is the circumference of this circle?

Pi button, nearest whole #

• 50

• 25

• 125

If a circle has a radius of 15, what is the length of the diameter?

• 47

• 7.5

• 30

What is the radius, if a diameter is 18?

• 36

• 9

• 57

Steven purchases a bowl. The diameter of the bowl is 14 cm. What is the circumference of the bowl?

• 28 cm
• 43.98 cm
• 87.96 cm
• 7 cm

Determine the radius of the penny

• 59.66 mm
• 9.5 mm
• 38 mm
• 119.32 mm

What is the circumference of a circle with a radius of 8?

• 8π

• 4π

• 16π

• 2π