PPT: Grandmother’s Quilt | Mathematics (Maths Mela) Class 5 - New NCERT PDF Download

 Page 1


Grandmother's 
Quilt
Page 2


Grandmother's 
Quilt
What is Perimeter?
Derived from Greek words: peri (around) + metron (measure).
Definition: Distance 
around a plane figure 
(sum of all sides).
Units: cm, m, km, etc.
Key Note: Perimeter tells about the boundary, not the inside.
Page 3


Grandmother's 
Quilt
What is Perimeter?
Derived from Greek words: peri (around) + metron (measure).
Definition: Distance 
around a plane figure 
(sum of all sides).
Units: cm, m, km, etc.
Key Note: Perimeter tells about the boundary, not the inside.
Perimeter of a Rectangle
A rectangle is a plane figure whose opposite sides (facing each other) are of equal lengths.
So, we have two equal lengths and two equal breadths.
Perimeter of a rectangle = length + 
breadth + length + breadth
= length + length + breadth + breadth
= 2 × length + 2 × breadth
= 2 × (length + breadth) = 2 × (l + b)
Perimeter of rectangle = 2 × (length + breadth)
Page 4


Grandmother's 
Quilt
What is Perimeter?
Derived from Greek words: peri (around) + metron (measure).
Definition: Distance 
around a plane figure 
(sum of all sides).
Units: cm, m, km, etc.
Key Note: Perimeter tells about the boundary, not the inside.
Perimeter of a Rectangle
A rectangle is a plane figure whose opposite sides (facing each other) are of equal lengths.
So, we have two equal lengths and two equal breadths.
Perimeter of a rectangle = length + 
breadth + length + breadth
= length + length + breadth + breadth
= 2 × length + 2 × breadth
= 2 × (length + breadth) = 2 × (l + b)
Perimeter of rectangle = 2 × (length + breadth)
Example 1: The length of the sides AB and CD of the rectangle ABCD are 3 cm each and the length of the sides 
BC and DA are 6 cm each. Find its perimeter.
Ans: Perimeter of rectangle ABCD,
= 3 cm + 6 cm + 3 cm + 6 cm = 18 cm
Using the formula,
Perimeter of the rectangle ABCD = 2(l + b)
= 2 × (6 + 3) cm
= 2 × 9 cm = 18 cm
Thus, the perimeter of the rectangle ABCD is 18 cm.
Page 5


Grandmother's 
Quilt
What is Perimeter?
Derived from Greek words: peri (around) + metron (measure).
Definition: Distance 
around a plane figure 
(sum of all sides).
Units: cm, m, km, etc.
Key Note: Perimeter tells about the boundary, not the inside.
Perimeter of a Rectangle
A rectangle is a plane figure whose opposite sides (facing each other) are of equal lengths.
So, we have two equal lengths and two equal breadths.
Perimeter of a rectangle = length + 
breadth + length + breadth
= length + length + breadth + breadth
= 2 × length + 2 × breadth
= 2 × (length + breadth) = 2 × (l + b)
Perimeter of rectangle = 2 × (length + breadth)
Example 1: The length of the sides AB and CD of the rectangle ABCD are 3 cm each and the length of the sides 
BC and DA are 6 cm each. Find its perimeter.
Ans: Perimeter of rectangle ABCD,
= 3 cm + 6 cm + 3 cm + 6 cm = 18 cm
Using the formula,
Perimeter of the rectangle ABCD = 2(l + b)
= 2 × (6 + 3) cm
= 2 × 9 cm = 18 cm
Thus, the perimeter of the rectangle ABCD is 18 cm.
Perimeter of a Square
A square is a plane figure whose all four sides are of equal lengths.
Perimeter of a square = 
side + side + side + side
= 4 × side
Perimeter of a square = 4 × length of one side