3rd Grade Area Lesson (Free PDF)
This area lesson for 3rd Grade covers area (Common Core 3.MD.C.5, 3.MD.C.6, 3.MD.C.7), with a free PDF to print.
Area counts how many unit squares fit inside a flat shape, leaving no gaps and no overlaps. The answer is written in square units, like square inches. A rectangle that is 7 long and 5 wide has 7 times 5, or 35, square units. Odd shapes can be cut into rectangles whose areas are added.
Grade 3 · Common Core State Standards: 3.MD.C.5, 3.MD.C.6, 3.MD.C.7
Key facts in this area lesson
- A unit square has sides 1 unit long and an area of 1 square unit.
- Rectangle area = length × width (rows times squares in each row).
- Area is always written in square units, such as square feet.
- The distributive property splits a big rectangle into two small ones: 8 × 6 = (5 × 6) + (3 × 6).
- Find the area of an L-shape by cutting it into rectangles and adding.
What does area mean?
Area is the amount of flat surface inside a shape. To measure it, tile the shape with unit squares: no gaps, no overlaps. Then count the tiles.
This rectangle holds 3 rows of 4 squares. Count them all and you get 12, so the area is 12 square units.
How can you find the area of a rectangle?
Counting every square takes time. Since a rectangle is built from equal rows, multiplication is a faster way to count.
- Read the two side lengths. Check that they use one unit.
- Multiply them.
- Name the answer in square units.
Example. Maya has a rug 7 feet long and 5 feet wide. Its area is \(7 \times 5 = 35\), so the rug covers 35 square feet.
Because \(7 \times 5 = 5 \times 7\), swapping the two sides gives the same area.
How does the distributive property help?
Any rectangle can be cut into two smaller rectangles. Work out each small area, then add them. Cutting \(8 \times 6\) into \(5 \times 6\) and \(3 \times 6\) makes \(30 + 18 = 48\).
How can you find the area of an L-shaped figure?
Some shapes have only square corners. Slice one into rectangles, find the area of each piece, and add the pieces.
Top piece: \(4 \times 2 = 8\). Bottom piece: \(10 \times 3 = 30\). Put them together: \(8 + 30 = 38\) square feet in all.
Area lesson: questions and answers
How is area different from perimeter?
Area counts the surface inside a shape using square units. Perimeter measures the trip around the edge using plain length units.
Why is area measured in square units?
Area counts unit squares that cover a shape. Each one is a square, so the answer is in square inches, square feet, or square centimeters.
Does it matter which side I call the length?
No. Multiplication can be done in either order, so 6 × 9 and 9 × 6 both give 54. The area stays the same.
How can I find a missing side when I know the area?
Think of a multiplication fact with a missing factor. If the area is 40 and one side is 5, ask what number times 5 makes 40. The other side is 8.
How do I find the area of a shape that is not a rectangle?
If it has only right angles, cut it into rectangles, find each area, and add. Cut it so the pieces do not overlap.
How to use this area lesson
Read the definitions first, then follow the worked method line by line and redo the example on paper without looking. When every step makes sense, move on to the worksheet, then check yourself with the quiz.
Download the area lesson as a PDF with the button below and keep it with your notes.
All Grade 3 chapters: Grade 3 math.
