Area and Land Measurements
Primary 4 · Mathematics
Area and Land Measurements
Lesson 1 of 5
15 min
Let's begin
Mutesi's mother is putting square tiles on the floor of a new kitchen in Rubavu. "How many tiles will we need?" she asks.
Mutesi looks at the plan of the floor. She starts counting squares. She is measuring the area of the floor!
Today you will learn what area is and how to measure it with squares.
The area of a shape is the amount of flat surface it covers. A table top, a classroom floor, a football pitch and a farm all have an area.
Area is not the same as the length around the edge. The edge is the perimeter. The area is the space inside.
A unit square is a square with sides of 1 unit. To measure area, cover the shape with unit squares. They must touch edge to edge, with no gaps and no overlaps. Then count them.
Shape A covers 3 rows of 5 squares. Its area is 15 square units. Shape B covers 8 squares on top and 4 underneath. Its area is 12 square units.
If a square is cut in half, two halves make one whole square. 7 whole squares and 2 half squares make 8 square units.
We read 15 cm² as "15 square centimetres".
Uwase covers a table with big square tiles. Mugisha covers the same table with small square tiles. The table does not change, so the area is the same. But Mugisha needs more tiles, because each one covers less. It takes more small squares than big squares to cover the same shape.
Open the Area Builder simulation and choose the Explore screen. Drag squares onto the board to build shapes. Watch the area change as you add each square.
Tip
No gaps, no overlaps. Cover the whole shape with squares that touch edge to edge, then count. Always say the unit: square units, cm² or m².
Work each one in your exercise book first. Then tap Show answer to check.
A rectangle is covered by 4 rows of 6 unit squares. What is its area?
Answer: 24 square units, because 4 × 6 = 24.
A shape covers 7 whole squares and 2 half squares. What is its area?
Answer: 8 square units. The two halves make 1 whole square, and 7 + 1 = 8.
Which unit would you use for the area of a page in your exercise book: cm² or m²?
Answer: cm². A page is small.
Which unit would you use for the area of your classroom floor: cm² or m²?
Answer: m². A floor is big.
Keza covers a mat with 10 big square tiles. Ishimwe covers the same mat with smaller square tiles. Will he need more tiles or fewer tiles?
Answer: More tiles. Each small tile covers less of the mat.
What you learned today
Sources and credits
The stories, Rwandan examples, drawings and practice questions were written by Ganzaa.
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