Unit 4B mid review

Is the red line a radius or diameter of the circle?

• Radius
• Diameter

The formula for the circumference, C, of a circle with radius r is given. 

C=2πr

What is the circumference of the circle?

• 50.24 cm
• 200.96 cm
• 25.12 cm
• 16 cm

Is the red line a radius or diameter of the circle?

• Radius

• Diameter

The formula for the circumference, C, of a circle with radius r is given. 

C=2πr  or C=πd  

Elsie bought a circular rug that is 9 feet in diameter. What is the circumference of the rug rounded to the nearest tenth of a foot?

• 4.5 feet

• 14.1 feet

• 28.3 feet

• 56.5 feet

The formula for the circumference, C, of a circle with radius r is given. 

C=2πr  or C=πd  

Alex has trained his puppy, Popper, to jump through a ring. According to Alex's measurements and calculations, the ring has a diameter of 3.5 feet. What is the ring's circumference (use 3.14 for pi)?

• 11.32 ft
• 12.25 ft
• 10.99 ft
• 8.75 ft

• 81π
• 9π
• 3π
• 6π

A circular swimming pool is 21 feet in diameter.
How many feet around is the pool?

• 10.5 ft
• 42 ft
• 65.94 ft
• 131.95 ft

What is the circumference?

• 36
• 12.56
• 56.52
• 113.04

Daniel wants to buy cookies for her friend. The radius of a cookie is 5 inches. What is the cookie’s circumference?

• 10 in
• 2.5 in
• 15.7 in
• 31.4 in 

The diameter of a circle is 3 centimeters. What is the circumference?

• 11.5cm2
• 9.42 cm2
• unicorns are awsome
• 45.3 cm2