Circles and Circumference

what is the formula for finding area of a circle

• C = π r²

• A = π r²

• A = π r² / 2

• C = 2 π r

what is the radius of the inner circle?

• 12 in

• 8 in

• 8 ft

• 4 in

what is the diameter of the inner circle

• 16 in

• 12 in

• 4 in

• 8 ft

what is the formula for finding the area of a semi-circle

• A = π r²

• C = π r²

• A = π r² / 2

• A = 2 π r

Which of the following names a diameter?

• segment AC

• segment DB

• segment AB

• segment BC

What is circumference?

• The distance around a circle.

• The space inside the circle.

• A line from side to side passing through the center.

• A line from the center to the side.

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

The radius is....

• a line that crosses through the center and touches each edge 

• the center point of a circle 

• a line from the center point to the edge of the circle

• an element in science