Q31Written answer
The square of 5.5 is _________.
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Worked solution
Solution:-
The square of 5.5 is 30.25.
= 5.52 = 5.5 × 5.5 = 30.25
NCERT Exemplar · Class 8 · Maths
Chapter 3: Squares and Square Roots & Cubes and Cube Roots
Practice each question, then open the answer or worked solution.
Questions
142 questionsQ32Written answer
The square root of 5.3 × 5.3 is _________.
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Worked solution
Solution:-
The square root of 5.3 × 5.3 is 5.3.
= √(5.3 × 5.3)
= √(28.09)
= 5.3
Q33Written answer
The cube of 100 will have _________ zeroes.
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Solution:-
The cube of 100 will have 6 zeroes.
= 1003
= 100 × 100 × 100
= 1000000
Q34Written answer
1m2 = _________ cm2.
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Worked solution
Solution:-
We know that, 1m = 100cm
Then,
1m2 = 10000 cm2
Q35Written answer
1m3 = _________ cm3.
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Worked solution
Solution:-
We know that, 1m = 100cm
Then,
1m3 = 1000000 cm3
Q36Written answer
Ones digit in the cube of 38 is _________.
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Worked solution
Solution:-
Ones digit in the cube of 38 is 2.
We know that,
38 × 38 × 38 = 54,872
Q37Written answer
The square of 0.7 is _________.
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Worked solution
Solution:-
The square of 0.7 is 0.49.
= 0.72
= 0.7 × 0.7
= 0.49
Q38Written answer
The sum of first six odd natural numbers is _________.
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Worked solution
Solution:-
The sum of first six odd natural numbers is 36.
The first six odd numbers are 1, 3, 5, 7, 9, and 11
Then,
Sum of first six odd numbers = 1 + 3 + 5 + 7 + 9 + 11
= 36
Q39Written answer
The digit at the ones place of 572 is _________.
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Worked solution
Solution:-
The digit at the ones place of 572 is 9.
We know that, 3 or 7 at the units place ends in 9.
= 572
= 57 × 57
= 3249
Q40Written answer
The sides of a right triangle whose hypotenuse is 17cm are _________ and _________.
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Worked solution
Solution:-
For every natural number m > 1, 2m, m2 –1 and m2 + 1 form a Pythagorean triplet.
Now,
m2 + 1 = (2m)2 + (m2 – 1)2
Where,
m2 + 1 = 17
m2 = 17 – 1
m2 = 16
m = √16
m = 4
Then,
2m = 2 × 4
= 8
And,
m2 – 1 = 42 – 1
= 16 -1
= 15