Circumference of circles

The definition of diameter is

• distance from the center of any point on the circle

• distance across the circle through the center

• distance from one point to another

• distance around the circle

The definition of radius is

• distance from one point to another point

• distance around the circle

• distance from the center to any point on the circle

• distance across the circle through the center

what is the formula for finding diameter

• r = 2 d

• d = 2 r

• a = m c²

• c = π 2 r

what is the formula for finding area of a circle

• C = π r²

• A = π r²

• A = π r² / 2

• C = 2 π r

If the radius of a circle is 4 inches, what is the diameter?

• 2 inches

• 2 feet

• 4 inches

• 8 inches

What is the Circumference of this circle? 

(Use 3.14 for  $\pi$  )

• 452.39 cm

• 452.16 cm

• 75.36 cm

• 75.40 cm

A bicycle tire has a diameter of 27 inches. What is the radius?

• 27pi
• 13.5
• 81
• 25pi

What is the Circumference of this circle? 

(Use 3.14 for  $\pi$  )

• 452.39 cm

• 452.16 cm

• 75.36 cm

• 75.40 cm

What is the perimeter of the semi-circle?

• 11 yd
• 17.27 yd
• 34.54 yd
• 28.27 yd

what is the circumference of this circle ?

• 3.14 cm 
• 37.68 cm
• 24 cm
• 68.4 cm