Review 15

The radius of a circle is ​ (a)   the diameter.

• half
• twice
• triple

What is the area of this circle?

• 201.06 square meters

• 50.24 square meters

• 123.12 square meters

• 25.12 square meters

A circle has a diameter of 17 inches. What is the area?

• 26.69 in²

• 226.87 in²

• 72.25 in²

• 53.38 in²

What is the circumference of this circle ?

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

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

• 20ft
• 5ft
• 31.4ft
• 62.8ft

If my diameter is 19 inches, what is my radius?

• 38 inches
• 9.5 inches
• 59.66 inches
• 119.32 inches

Does this picture show the diameter or radius of a circle?

• Diameter
• Radius

Does this picture show the diameter or radius of a circle?

• Diameter
• Radius

A cruise ship has a large, circular window. It has a diameter of 6 meters. What is the window's approximate circumference?

• 3 m 
• 9.42 m
• 12 m
• 18.84 m

 What is the formula for circumference of a circle given the diameter?

• C = π r

• C = π d

• C = 2 π r

• C = 2 π d