Question

What is the perimeter of each of the following figures? What do you infer from the answers?

Answer 1

(a) \(\text{Perimeter of square }= 4 \times side\) 
= \(4 \times 25 = 100\) \(cm\) 

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(b) \(\text{Perimeter of rectangle} = 2 \times (length + breadth)\) 
= \(2 \times (40 + 10)\) 
= \(2 \times 50 = 100\) \(cm\) 

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(c) \(\text{Perimeter of rectangle }= 2 \times (length + breadth)\) 
= \(2 \times (30 + 20)\) 
= \(2 \times 50 = 100 \) \(cm\) 

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(d) \(\text{Perimeter of triangle} = \text{Sum of all sides}\) 
= \(30\; cm + 30 \;cm + 40\; cm\) 
= \(100\) \(cm\) 

Thus, all the figures have same perimeter. 

Answer 2

(a) Length of the side of the given square = 25 cm
So, Perimeter = 4 × side
= 4 × 25 = 100 cm.
(b) Length of the given rectangle = 40 cm
Breadth of the given rectangle = 10 cm
So, Perimeter = 2 × (length + breadth)
= 2 × (40 + 10)
= 2 × 50 = 100 cm
(c) Length of the given rectangle = 30 cm
Breadth of the given rectangle = 20 cm
So, Perimeter =  2 × (length + breadth)
= 2 × (30 + 20)
= 2 × 50 = 100 cm
(d) Perimeter of the triangle = Sum of all three sides
= 30 cm + 30 cm + 40 cm
= 100 cm
So, from all this we get, figures have same perimeter.