Grades 3 to 6 · 8 lessons
Perimeter, area and volume
Free perimeter, area and volume course for grades 3 to 6. Eight lessons: perimeter, area, composite shapes, triangles and volume.
Each lesson has one idea, one worked example, practice questions and one puzzle. Work through the list in order, or jump to the lesson you need. Every lesson has a matching practice page with ten more questions and answers.
All eight lessons are ready. Start with lesson 1, and use the practice page after each lesson to check that the idea has sunk in.
Lessons
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Perimeter of polygons
Add every side to walk all the way around a shape.
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Area by counting squares
Cover a shape with unit squares and count them.
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Area of rectangles
Length times width, and why rows of squares work.
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Area of composite shapes
Split into rectangles, find each area, then add.
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Area of triangles and parallelograms
Base times height, and half of it for a triangle.
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Volume by counting cubes
Fill a solid with unit cubes and count the layers.
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Volume of rectangular prisms
Length times width times height.
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Real-life area and volume problems
Choose perimeter, area or volume, then compute.
What you will learn
The course starts with perimeter, the distance around a shape, and the simple habit of adding every side. Next you cover area: counting unit squares, then the rule for rectangles, then splitting composite shapes into rectangles and adding the parts. Triangles and parallelograms come after that, with the base and the perpendicular height. The last three lessons move into three dimensions: volume by counting unit cubes, the length × width × height rule for rectangular prisms, and real-life problems where the question decides whether you need perimeter, area or volume.
How to use the course
- Read one lesson. It takes about five minutes.
- Study the worked example and the diagrams.
- Answer the five "Try it" questions and check your answers.
- Open the practice page for ten more questions.
- Move to the next lesson when you feel steady.
There are 8 lessons and 8 practice pages, all free and without an account.
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