Right Angles, Squares and Rectangles
Primary 1 · Mathematics
Right Angles, Squares and Rectangles
Lesson 5 of 5
12 min
Let's begin
Mutesi walks home from school with her brother.
She names shapes all the way home: the gate, a window, a mat.
Her brother points at a big box and says square. Today you will see what he missed.
A box is not flat. You can hold it in two hands.
A square is flat. You can draw it on paper.
So do not name the whole box. Name one flat side of it.
Put the box down. Look at the side facing you. That flat side is a rectangle.
Careful! A box is not a square. A jerrycan is not a square either. Say which flat side you mean.
Test each one with your book corner and your eyes.
| Thing | Shape of the flat side |
|---|---|
| A door | rectangle |
| A window pane | rectangle |
| A floor tile | square |
| The cover of your exercise book | rectangle |
| A sleeping mat | rectangle |
| The flat side of a brick | rectangle |
Ask the same question every time. Are all 4 sides the same length?
Yes gives a square. Two long and two short gives a rectangle.
Open your exercise book at a clean page.
Step 1 Make 5 dots in a row, evenly spread out.
Step 2 Make 4 more rows of dots under it.
Now you have a grid of dots to join up.
Step 1 Put your pencil on a dot. Count 3 dots along the row.
Step 2 Draw a straight line to that dot with your ruler.
Step 3 Now count 3 dots down. Draw.
Step 4 Count 3 dots back, then 3 dots up to where you started. Draw.
Every side counted 3 dots, so all 4 are the same length. You drew a square.
Start at the first dot in the top row, so you do not run out.
Count 4 dots along. Then count 2 dots down.
Then 4 dots back and 2 dots up.
Two long sides and two short sides. You drew a rectangle.
Test all the corners with your book. No gaps!
Squares and rectangles in a village, with square corners marked.
Go on a square hunt, then hunt in your own room.
Tip
Name the flat side
A box is a box. The side facing you is a rectangle.
Point with your finger at the exact side you mean, then name it.
Point at each thing before you answer. Then tap Show answer to check.
What shape is a door?
Answer: a rectangle. Two long sides, two short sides, 4 right angles.
A floor tile has 4 sides all the same length. What shape is it?
Answer: a square. All 4 sides match and all corners are right angles.
Gatete says his box of soap is a square. What should he say?
Answer: the flat side of the box is a rectangle. The box itself is not flat.
Draw a rectangle on your dot grid: along 4 dots, down 2 dots.
Answer: check it. Opposite sides match and every corner is a right angle.
Count the rectangles in your room. Test three of them.
Answer: most rooms give you the door, the window and a mat.
What you learned today
All three are free to read. Read them with someone at home.
Zigoronzoye n'izigororotse is in Kinyarwanda, free to read from the Global Digital Library. A square and a rectangle have straight sides, so sort every thing on the page: straight, or curved?
Who Will Win? is in easy English, free to read from the Global Digital Library. Mr Square and Ms Rectangle build things out of their own shapes.
Go on one more shape hunt in Cube Cat, Cone Cat, also in easy English and free to read from the Global Digital Library. The cat finds shapes in everyday things, just like you did on the way home. Point at every flat side you can name.
Quick check
A box is a square.
