3. • A rectangle is a 2-D shape With four
sides and four right angles (90 ̊)
• The opposite sides of rectangle are
equal and parallel
• It has different length and breadth.
9. Area
• Area is the amount of space inside the boundary of a
flat surface.
• All the sides of this square are 1 cm long-
• What would be the area of this square?
• Formula of area of square is = side x side
• So the area of this square would be
= 1cm x 1cm = 1 square cm or 1cm²
Area 1cm1cm
1cm
1cm
10. • So the area of such two squares would be 2cm²
• And the area of such 4 squares would be 4 cm²
Area
AreaArea
Area
AreaArea
12. Perimeter
• Length of the boundary or the distance around
the outside edge of a flat surface is called
perimeter.
• The sides of the given square are 1 cm long
• So its perimeter or boundary is = 1cm
+1cm +1cm +1cm= 4cm
• Formula of perimeter of square= 4xSide
Area 1cm1cm
1cm
1cm
14. 2cm
6cm
6cm
The boundary or perimeter of
rectangle 1 is-
2cm+6cm+2cm+6cm=16cm
2cm
4cm
4cm
3cm
3cm
The number of squares in both the
rectangles is same-12.
So the area of both of these would be
same-12 cm²
But the perimeter would be
different as given below
15. The perimeter of the rectangle-4
would be the longest
12cm
12cm
1cm
1cm
Perimeter of rectangle-4 is =
12cm+1cm+12cm+1cm =
26cm
16.
17. The area of different stamps
Stamp Number of
squares
cover
Area
A 18 18 Square cm.
B 8 8 Square cm.
C 6 6 Square cm.
D 12 12 Square cm.
E 4 4 Square cm.
F 12 12 Square cm.
19. What is the area
of this shape? It covers 20
squares so the
area is 20
square cm.
What is the
area of
green part?
Yellow and green parts
cover 20 squares so
the area of yellow and
green parts
altogether is 20
square cm.
But the green part is
the half part of whole
rectangle so its area
will be ½ of 20= 10
square cm.
Shape A
Shape B
Area of shape A and B
20. Shape F
Shape F covers four squares
that are more than half-
filled,
four squares that are less
than half-filled,
and
four complete squares.
Area of figure F = area of
four squares more than half-
filled squares + area of four
complete squares = (4 + 4)
square cm = 8 square cm
What is the area
of this shape?
Area of shape F
21. Shape c
Shape C covers two complete
squares,
two squares that are more than
half-filled,
and
two squares that are less than
half-filled.
Area of figure C = area of two
complete squares + area of two
squares more than half-filled
= (2 + 2) square cm = 4 square
cm
What is the area
of this shape?
Area of shape C
22. Area of shape E and D
Shape E covers 18 complete
squares and
6 half squares.
6half squares=
3 complete squares
SO its area= 18+3=21 square
cm.
⅟2 1
7
5432
10 11 12 ⅟2
6
9
17 18 ⅟215
8
1613 14
⅟2
⅟2
⅟2
Shape E
Shape D
1 2 4 53⅟2 ⅟2
Shape D covers 5 complete
squares and
2 half squares.
2half squares=
1 complete squares
SO its area= 5+1=6 square
cm.
23. We can find out the area of a rectangle
without the grid.
Length=8cm
Width=4cm
Formula of Area of Rectangle = length x breadth
So the area of this rectangle= 8cmx4cm= 32 cm²
24. Area of blue Triangle
Blue triangle is the half part
of Big rectangle. The area
of big rectangle=
5cm x 4cm= 20 cm²
So the area of blue triangle
would be half of the area of
Big rectangle= 20/2= 10 cm²
25. Area of Red Triangle
•In Red triangle there are two halves of
two different Rectangles
•(Red triangle=half part of orange
rectangle + half part of green
rectangle)
Area of Orange rectangle= 12 cm² and half of this = 6 cm²
Area of green rectangle= 8 cm² and half of this = 4 cm²
So the area of Red triangle = 6 cm²+ 4 cm²= 10 cm²
6 cm²
4 cm²
26. Here is a rectangle of area 20 square cm.
(a) Draw one straight line in this rectangle to divide it
into two equal triangles. What is the area of each of
the triangles?
(b) Draw one straight line in this rectangle to divide it
into two equal rectangles. What is the area of each of
the smaller rectangles?
(c) Draw two straight lines in this rectangle to divide it
into one rectangle and two equal triangles. • What is
the area of the rectangle? • What is the area of each
of the triangles?
27. (a) The given rectangle is divided into two equal
triangles by drawing a line as shown below.
Area of rectangle
= 20 square cm Area of each triangle
=12of area of rectangle
= (20 ÷ 2) square cm
= 10 square cm
28. (b) The given rectangle is divided into two
equal rectangles by drawing a line as shown
below.
Area of rectangle
= 20 square cm Thus, area of each small rectangle
=12of area of rectangle
= (20 ÷ 2) square cm = 10 square cm
29. (c) The given rectangle is divided into one rectangle
and two equal triangles by drawing 2 lines as shown
below.
in the red shaded region, we have 2 completely filled squares
and
2 squares that are more than half-filled.
Thus, the area of red triangle = 4 square cm
Similarly, the area of green triangle = 4 square cm
Now, the area of remaining portion i.e. the rectangle contains 12
completely filled squares.
• Thus, the area of rectangle = 12 square cm. • Area of each of the
triangle is 4 square cm.
30. Puzzles with Five Squares Measure the side of a small
square on the squared paper on page 45. Make as many
shapes as possible using 5 such squares. Three are drawn
for you.