Circles

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

• C = π r
• C = 2 π r
• C = π d
• C = 2 π d

What is the diameter?

• 8
• 16
• 10
• 4

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

Find the area of the circle

• 43.96
• 153.86
• 87.82
• 307.72

What is the radius of this circle?

• 12cm
• 6cm
• 24cm
• 3cm

What is the circumference?

• 50.24

• 25.12

• 24.5

• 18.3

find the area of the circle with radius 3 cm below.

• 100 cm²

• 225 cm²

• 9 cm²

• 28.26 cm²

The Carillo family has a circular swimming pool with a diameter of 10 feet. Find the area of the pool cover to the nearest tenth.

• 94 ft²

• 53.4 ft²

• 70.9 ft²

• 78.5 ft²