Review Circles

What is the formula for circumference of a circle?

• C = d⋅π

• C = 2⋅π⋅r

• C = π⋅r²

• C = d⋅π and
  C = 2⋅π⋅r

What is the formula for area of a circle?

•  π⋅r²
  

• = d⋅π

• = 2⋅π⋅r

• = 2⋅r

What is the diameter?

• 8

• 16

• 10

• 4

What is the radius?

• 18

• 72

• 38

• 14

A circle's diameter is 13 cm.  What is the approximate circumference?  

• 6.5 cm

• 13 cm

• 40.8 cm 

• 20.4 cm 

The radius of a circle is 3 cm.  What is the circle's diameter?

• 9.4 cm

• 6 cm

• 18.8 cm

Find the area of the circle

• 43.96

• 153.86

• 87.82

• 307.72

• 122.46 mi²
• 122. 45 mi²
• 175.84 mi²
• 175.85 mi²

A bike wheel has a diameter of 10 ft. What is the circumference of the wheel?

• 10π feet 

• 3.14π feet

• 3.14 feet

Determine the radius of the penny

• 59.66 mm

• 9.5 mm

• 38 mm

• 119.32 mm