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Perimeter of Polygons In Word Problems

3.MD.8
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Grade 3 Measurement - 3.MD.8

How to Determine the Perimeter of Polygons? Any two-dimensional shape that is made of straight lines is known as a Polygon. There are two types of polygons including regular and irregular. The polygons with equal lengths and equal angles are known as the regular. Irregular are the ones that do not have equal lengths or equal angles. The perimeter of a polygon is the length of the entire boundary that makes up the whole shape. For Regular Polygons - It is a square that has equal sides, and it is a regular polygon. All you have to do is identify the length of one side and multiply it with the number of sides. Considering the above example; The perimeter of the square = 20 x 4 = 60 for a total of 60 inches. The perimeter of regular polygon = Length of one side x number of sides Perimeter of the Irregular Polygon - In the case of an irregular polygon, the sides are not of an equal length. To calculate the perimeter of the shape, you just have to sum all the sides. Take the above example of a rectangle where the lengths of the sides are 2,2,3,3. Perimeter of rectangle= 2 +2 + 3 + 3 = 10 m. The perimeter of irregular polygon=sum of all sides. Through these worksheets and lessons students will learn how to add up the perimeter of polygons when the measures are in story problem format.

Printable Worksheets And Lessons




Homework Sheets

Help Coach Wilson plan his next practice and find the missing sides.

  • Homework 1- Coach Wilson is working with his team to get them in shape for the season. The school has 4 fields that the players can run around. Find the perimeter of each field and answer the questions below.
  • Homework 2- If the perimeter of all the regular shapes below is 30 cm, find all the missing sides.



Practice Worksheets

Jeff is one forgetful painter. How is he ever going to buy paint?

  • Practice 1- Jeff was hired to paint several rooms in a home. He has a diagram of the rooms that he needs to paint. He forgot to write all the lengths of the walls. Find the length of the missing walls below.
  • Practice 2- Find the perimeter of every polygon. This is a measure of the sum of all sides. Make note of the units of measure used in each problem and properly label your answers.



Math Skill Quizzes

You will some challenging word problems in here.

  • Quiz 1- What is the width of a rectangle that has a perimeter of 28 cm and a length of 8 cm?
  • Quiz 2- Circle all of the rectangles that have the same value.


Tricks to Determining This Measure

We covered the first method in detail above, but we will restate it anyway. If you are working with a regular polygon, just multiply the length of one side by the number of sides that the figure has. To right it in a shortened form: regulars = length of one side (l) times the number of sides (n) or ln. What about when we have an irregular shape where the length of sides differs? In this case, we just determine the length of all the sides and then find their sum. You can also use geometry to help you with this measure. You find that this is helpful when determine distances. You would start by plotting the points on a coordinate grid. Connect all the points by drawing lines. You can then determine the length of these lines by simply counting them over the grid. In many cases you will want to determine the distance of the hypotenuse side. You can determine this by using the distance formula. Once you get some practice with this skill and can clearly tell the differences between regular and irregular shapes, this will become easy.