2. In this chapter, We are going to tell you about chapter
perimeter and area .This is very interesting chapter
where we can learn about perimeter and area so, when
we heard the chapter name perimeter and area, you
have a question that “What is perimeter and area, and
where we can use it in our life “ In our life we see many
different types of bridges so however , people think that
how the engineer construct the bridge and why it is so
perfect and stable so this is because the engineer use
the concept of perimeter and area .
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3. In this chapter you will learn about :
› Calculate the area and perimeter of a square
› Calculate the area and perimeter of a rectangle
› Calculate the area of the closed figure which is a combination of
square(s) and rectangle(s)
› Calculate the area of triangle
› Calculate the perimeter and area of a parallelogram
› Calculate the perimeter and area of the circle
› Calculate the area between two concentric circles
› Calculate the area of the figure which is a combination of different
shapes
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4. Q1 what is perimeter and area
› Ans1 - Perimeter: The sum of all side is known as perimeter.
› Example: Like you are going to do your lunch and you see that today you bring
sandwich so the length of one side of sandwich is 5 cm and another side is 6 cm so,
what is the perimeter of the sandwich. At this time you use formula of perimeter is sum
of all side or you use perimeter of rectangle because the length is 5 and the breadth is
6 so it is not a square so we use perimeter of rectangle =2(length + breadth).
› Ans2 – Area: The area is the region boundary by the shape of an object.
› Example : like a engineer constructed a building of 10 floors but they doesn't put the
tiles yet in the flats so the engineer measured the length and the breadth of the flats is
10m and 14m so the area of the flat is 140m because the formula of area of the
rectangle is (length x breadth) and they want to put in all 10 floors is (140 x 10 =1400m)
the area of all 10 floor’s flats is 1400m.
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5. Key terms of perimeter and area
› Altitude : The altitude of a triangle is the perpendicular drawn from the vertex of
the triangle to the opposite side.
› Base : a base is a side of a polygon or a face of a polyhedron, particularly one
oriented perpendicular to the direction in which height is measured, or on what is
considered to be the "bottom" of the figure.
› Circumference : the perimeter of circle is known as circumference we use the
formula (2πr = 2*22/7*r) means the value of π is 22/7 or 3.14 and the value of r
is radius , the radius is the half of circle’s diameter.
› Perpendicular : Two distinct lines intersecting each other at 90° is known
perpendicular.
› Congruent : Two shapes are congruent if they have the same shape and size.
› Parallelogram : A parallelogram is a special type of quadrilateral that has both
pairs of opposite sides parallel and equal.
› Pi (π) : the ratio of the circumference of any circle to the diameter of that circle is
known as pi (π). The value of π is 22/7 or 3.14 the π is use for measuring the
perimeter and area of the circle like 2*22/7*r and 22/7*r2.
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6. Formula
Perimeter
› Perimeter of rectangle = 2( l + b )
› Perimeter of square = 4 x side
› Perimeter of triangle = sum of all side
› Perimeter of circle = 2 πr
› Perimeter of parallelogram = 2
( b + h )
Area
› Area of rectangle = l x b
› Area of square = side x side
› Area of triangle = ½ x b x h
› Area of circle = πr2
› Area of parallelogram = b x h
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7. Questions with solution
› Q1: The length and breadth of the rectangular piece of land are 60m and 45m respectively . Find its area
.
› Ans: length = 60m , breadth = 45m
area of rectangle = l x b
= 60 x 45 m
=2700 m2
› Q2: Find the area of the square park whose perimeter is 48m .
› Ans : perimeter of square = 48m
48 = 4 * x
x = 48/4
x = 12
› Area of square = side x side
= 12 x 12 m
= 144 m2
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