85
Drawing shapes on squared paper
Textbook: Part 3, lesson 80, pp. 18–19
GoalDraw rectangles and squares on squared paper; turn squares into centimetres.
New words
square (cell) · katakgrid · to‘rshape · shaklline of symmetry · simmetriya o‘qi
Explanation
A square in your notebook has side 5 mm, so 2 squares make 1 cm. We draw a shape along the squares and count the sides. A rectangle of 10 by 4 squares is 5 cm long and 2 cm wide. Its perimeter is 5 + 2 + 5 + 2 = 14 cm.
Worked examples
10 squares = 5 cm, 6 squares = 3 cm, 8 squares = 4 cm.
A square has 4 lines of symmetry: two through the middle and two along the diagonals.
Class activity
“Shapes on squares”: the teacher says “8 squares long, 4 squares wide”. Children draw it, write the sides in cm and find the perimeter.
Practice
1
How many centimetres are 12 squares?
6
2
A rectangle with sides 10 and 4 squares: what is its perimeter in cm?
14
3
A square has side 8 squares. What is its perimeter in cm?
16
4
How many millimetres is the side of a notebook square?
5
5
Calculate in cm: 2 m 4 dm 5 cm + 1 m 3 dm = ? cm
375