1.8 - Perimeter, Circumference, and Area

1.8 - Perimeter, Circumference, and Area

by Steve Dull

​Today's Objectives:

• ​To find perimeter or circumference of basic shapes

• ​To find area of basic shapes

​Important Terms

• ​The perimeter (P) of a polygon is the sum of the lengths of its sides

• ​The area (A) of a polygon is the number of square units it encloses.

​Formulas

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​Important!

​When measuring area, use square units such as square inches, square feet, square miles.

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Fill in the Blank

Your yard measures 20 feet long by 30 feet wide. How much fence would you need to enclose the yard on four sides?

Fill in the Blank

Your yard measures 20 feet long by 30 feet wide. You are buying a bag of fertilizer to cover the entire yard. What is the area of your yard?

​Circumference

Fill in the Blank

A circle has a radius of 4 cm. What is its circumference? Use 3.14 for $$\pi$$ . Round your answer to two decimal places.

​Tread carefully

​Be sure to make note of whether you are given radius or diameter in the problem - the circumference formula uses diameter so if you need the radius you'll have to double it.

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Fill in the Blank

Fill in the Blank

A giant pizza at your neighborhood pizza place has a diameter of 18 inches. What is the area of the pizza? Give an exact answer in terms of pi 

​We can also find area of figures with irregular shapes

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Let's try one...

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Fill in the Blank

Find the area of the figure:

Poll

Select the image that best shows how well you think you understand area, perimeter, and circumference: