Home






Perimeter and Area | Instructions: | Suggested Lessons or Activities: | Special Features: | Other Related Modules and Useful Links:


Perimeter and Area




Printable Resources:
Area and Perimeter Primary


Area of Letters and Words Using Tiles


Letters and Words.PNG


© R. Mirshahi

Instructions:

  • Click one of the Area or Perimeter buttons to start a 5-minute practice. This resource generates a different shape each time. Every time you answer a question correctly, you earn a point. You can peek at the answer by clicking the "eye" button, but this would cost you a point that you get back when you click the right answer. The Reveal feature was added mainly for practice purposes when you need to check your answers and strategies before making a selection. The annotation feature was added to help students and teachers show their work and model problem solving strategies right on the page. Test your skills and practise to improve your personal high score!

Suggested Lessons or Activities:

  • There are many strategies that help students find perimeters and areas of a shapes. Help your students understand that perimeter is measurement of a line that goes around a shape and that is why it requires a linear unit like cm or m. This is very different from area which is the surface space inside the perimeter. That is why area requires a square unit. Here are some strategies and more will be discussed in the future.


Perimeter (Easy)

Perimeter is the distance around a shape. Measure the length of the line around each shape. Use the ruler or the grid to help you. Mark the linear units of perimeter as you count them so that you don't miss any section or count them more than once. See below:
Perimeter_Count_units.PNG

The shapes in this exercise are L-shaped hexagons. The perimeter of this shape is equal to that of its rectangular container. Since opposite sides are equal in a rectangle, add the sides (length and width) of the rectangle and double the sum to find the perimeter (7 + 7 = 14 and double that to get 28.)
Perimeter_Rectangle_Container.PNG


Perimeter (Advanced)

When the sides of a shape are not on the grid lines, you have to use the ruler to measure the sides of the triangle and add them to find the perimeter. If a side is 8.5, don't ignore the half (.5). Add all 3 sides and round your perimeter to match with the closest answer. This is a great exercise that tests the students' ability to apply their rounding and estimation strategies.
ruler to measure.PNG


Area Using a Grid (Easy)


Area is the amount of space inside a shape. It is measured in square units. Just count the number of grid squares inside the shape. Use the pen tool to mark the squares as you count them to make sure you don't miss any square or count it twice.
Area_CountSquare.PNG


Sometimes it is easier and faster to group the squares and skip-count. Here we skip-counted by 5 to find the area.
Area_SkipCount.PNG


The shape here can be divided into 2 rectangles. Multiply 2 sides of the rectangles to find the areas. Add the areas of the 2 rectangles. See below:
Area_Additive.PNG


Draw a rectangle around the shape. Multiply 2 sides of this large rectangle to find the area. Subtract the area of the missing part from the big rectangle. See below:
Area_Subtractive.PNG


Area (Advanced)


If you know the formula for calculating the area of a triangle, you can use it to arrive at the answers very quickly .
Area of a triangle (A = (b x h) ÷2) multiply the height of the triangle by its base and divide the answer by 2


The primary grade students who don't know how to multiply and divide, can first count the full squares on the grid and estimate the rest. For example, 2 half squares make a full square. Sometimes this is not easy to do. In these situations, students can also find the exact area of the triangles using the following strategy, which is based on the formula above.


Area_TriangleHalfRectangle.PNG

Special Features:

  • full screen to expand work space and minimize distraction
  • 5 minutes stopwatch to test your computational speed and strategies
  • suitable for any age. For older and more advanced students the focus can be development of faster mental math skills and strategies.
  • ability to reveal answers for students to check their answers for instant feedback and self-assessment
  • Scoreboard
  • ability to annotate right on the page to show strategies
  • simple, user-friendly tools (e.g., interactive ruler)
  • works very well with Interactive Whiteboards

Other Related Modules and Useful Links: