Let, ‘x’ be the number of steps and ‘y’ be the number of match sticks. Tabulate the values of ‘x’ and ‘y’ and verify the relationship y = 7x + 5.vThree more patterns are
From the table y = 7x + 5 is verified.
Try These (Text book Page No. 92)
Three more patterns are
From the table y = 7x + 5 is verified.
Try These (Text book Page No. 92)
vLet x denote the number of steps and y denote the area.
In the first shape let x = 1 and the area be 1 cm 2
when x = 2 : Area = 22 = 4 cm 2
whenx = 3 : Area = 32 = 9 cm 2 and so on.
Tabulating the values of x and y
From the table:
x = 1 ⇒ y = 1 2
x = 2 ⇒ y = 2 2
x = 4 ⇒ y = 4 2
x = 5 ⇒ y = 5 2
Hence the relationship between x and y is y = x 2
Let x denote the number of steps and y denote the area.
In the first shape let x = 1 and the area be 1 cm 2
when x = 2 : Area = 22 = 4 cm 2
whenx = 3 : Area = 32 = 9 cm 2 and so on.
Tabulating the values of x and y
From the table:
x = 1 ⇒ y = 1 2
x = 2 ⇒ y = 2 2
x = 4 ⇒ y = 4 2
x = 5 ⇒ y = 5 2
Hence the relationship between x and y is y = x 2
vLet x denote the number of steps and y denote the number of matchsticks used.
In step 1, x = 1 ⇒ y = number of mathsticks used is 1
In step 2, x = 2 ⇒ y = number of mathsticks used is 4
In step 3, x = 3 ⇒ y = number of mathsticks used is 7 and so on.
The values of v andy are tabulated as
x = 1 ⇒ y = 1 = 3(1) – 2
x = 2 ⇒ y = 4 = 3(2) – 2
x = 3 ⇒ y = 7 = 3(3) – 2
x = 4 ⇒ y = 10 = 3(4) – 2
From the table y = 3x – 2
Let x denote the number of steps and y denote the number of matchsticks used.
In step 1, x = 1 ⇒ y = number of mathsticks used is 1
In step 2, x = 2 ⇒ y = number of mathsticks used is 4
In step 3, x = 3 ⇒ y = number of mathsticks used is 7 and so on.
The values of v andy are tabulated as
x = 1 ⇒ y = 1 = 3(1) – 2
x = 2 ⇒ y = 4 = 3(2) – 2
x = 3 ⇒ y = 7 = 3(3) – 2
x = 4 ⇒ y = 10 = 3(4) – 2
From the table y = 3x – 2
(i) 1,2, 3, 4, 5, 6, 7. (ii) 1, 3, _____, _____, _____, _____. (iii) 1, _____, _____, _____, _____, (iv) _____, _____, _____, _____.v(i) 1,2, 3, 4, 5, 6, 7.
(ii) 1,3,6,10,15,21.
(iii) 1,4,10,20,35.
(iv) 1,5,15,35.
(i) 1,2, 3, 4, 5, 6, 7.
(ii) 1,3,6,10,15,21.
(iii) 1,4,10,20,35.
(iv) 1,5,15,35.
v
Try These (Text book Page No. 96)

Try These (Text book Page No. 96)
v
Common Properties:
The numbers filled by me are even numbers. Also they make triangular shape.
Yes, this pattern and the pattern given in situation 2 have the same properties.
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Common Properties:
The numbers filled by me are even numbers. Also they make triangular shape.
Yes, this pattern and the pattern given in situation 2 have the same properties.
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v(i) (d)
(ii) (a)
(iii) (c)
(iv) (c)
(v) (b)
Objective Type Questions
(i) (d)
(ii) (a)
(iii) (c)
(iv) (c)
(v) (b)
Objective Type Questions
v

(iv) 1,5,10,10,5,1
(iv) 1,5,10,10,5,1
(ii) 4,10,20,…
(ii) 4,10,20,…
(iii) 256
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(iii) 256
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Numbers in the 3rd slanding row are 1, 3, 6, 10, 15, 21,….
The squares are 1 2 , 3 2 , 6 2 , 10 2 . 15 2 , 21 2 ,…. = 1, 9, 36, 100, 225, 441,…
From the above table we can conclude that the squares of the triangular numbers are the sum of cubes of natural numbers.
Challenge Problems

Numbers in the 3rd slanding row are 1, 3, 6, 10, 15, 21,….
The squares are 1 2 , 3 2 , 6 2 , 10 2 . 15 2 , 21 2 ,…. = 1, 9, 36, 100, 225, 441,…
From the above table we can conclude that the squares of the triangular numbers are the sum of cubes of natural numbers.
Challenge Problems
v(i) Let the number of steps be x and the number of shapes be y.
Tabulating the values of x and y
From the table
x = 1 ⇒ y = 1 = 12
x = 2 ⇒ y = 4 = 22
x = 3 ⇒ y = 9 = 32
x = 4 ⇒ y = 16 = 42
Hence the relationship between x and y is y = x2.
(ii) Let the number of steps be x and the number of shapes be y.
Tabulating the values of x and y
From the table x = 1 ⇒ y = 1 = 1
x = 2 ⇒ y = 2 + 1 = 3
x = 3 ⇒ y = 3 + 2 = 5
x = 4 ⇒ y = 4 + 3 = 7
x = 5 ⇒ y = 5 + 4 = 9
Hence the relationship between x and y is y = 2x-1.
(i) Let the number of steps be x and the number of shapes be y.
Tabulating the values of x and y
From the table
x = 1 ⇒ y = 1 = 12
x = 2 ⇒ y = 4 = 22
x = 3 ⇒ y = 9 = 32
x = 4 ⇒ y = 16 = 42
Hence the relationship between x and y is y = x2.
(ii) Let the number of steps be x and the number of shapes be y.
Tabulating the values of x and y
From the table x = 1 ⇒ y = 1 = 1
x = 2 ⇒ y = 2 + 1 = 3
x = 3 ⇒ y = 3 + 2 = 5
x = 4 ⇒ y = 4 + 3 = 7
x = 5 ⇒ y = 5 + 4 = 9
Hence the relationship between x and y is y = 2x-1.