Circumference of Circles and Semicircles

 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

If you are given the diameter, how can you calculate the radius?

• Multiply the diameter by 2

• Subtract 2 from the diameter

• Add 2 to the diameter

• Divide the diameter by 2

How do you find the area of a circle?

A _____ is half of a circle.

• circumference

• pi

• semicircle

• composite figure

Steven purchases a bowl. The diameter of the

bowl is 14 cm. What is the circumference of the

bowl? Round to the nearest hundredth. Don't forget to label.

Find the circumference of a circle with a radius of 12.5 mm. Round to nearest hundredth. Don't forget to label.

Mrs. Wilson placed the welcome mat shown below on her front door step. What is the PERIMETER of her welcome mat in feet? Round to the nearest hundredth. Don't forget to label.

Shring's dining room table is round and has a radius of 4.5 feet. What is the tabletop's area?