RS Aggarwal Class 8 Math Third Chapter Squares and Square Roots Exercise 3H Solution

RS Aggarwal Class 8 Math Third Chapter Squares and Square Roots Exercise 3H Solution

EXERCISE 3H

OBJECTIVE QUESTIONS

Tick (√) the correct answer in each of the following:

(1) Which of the following numbers is not a perfect square?

Ans: (c) 5478.We know that a number ending in 2, 3, 7 or 8 is never a perfect square.

(2) Which of the following numbers is not a perfect square?

Ans: (d) 2222. We know that a number ending in 2, 3, 7 or 8 is never a perfect square.

(3) Which of the following numbers is not a perfect square?

Ans: (a) 1843. We know that a number ending in 2, 3, 7 or 8 is never a perfect square.

(4) Which of the following numbers is not a perfect square?

Ans: (b) 4787. We know that a number ending in 2, 3, 7 or 8 is never a perfect square.

(5) Which of the following numbers is not a perfect square?

Ans: 81000. We know that a number ending in an odd number of zeros is never a perfect square.

(6) Which of the following cannot be the unit digit of a perfect square number?

Ans: (d) 8. We know that a perfect square can’t have 2, 3, 7 or 8 as the unit digit.

(7) The of a proper fraction is

Ans: (b) smaller than the fraction.

(8) If n is odd, then (1+3+5+7+… to n terms) is equal to

Ans: (c) n²

(9) Which of the following is Pythagorean triplet?

Ans: (d) (8, 15, 17)

For every natural number m > 1, (2m, m² – 1, m² + 1) is a Pythagorean triplet.

Putting, 2m = 8 ⇒ m = 4

Thus, m² – 1 = 16 – 1 = 15

And, m² + 1 = 16 + 1 = 17.

(10) What least number must be subtracted from 176 to make it a perfect square?

Ans: (C) 7

This shows that (13)² < 176 by 7.

So, the least number to be subtracted from 176 is 7.

Required perfect square number = (176 – 7) = 169.

And: √169 = 13.

(11) What least number must be added to 526 to make it a perfect square?

Ans: (a) 3

526 + 3 = 529 ⇒ √529 = 23.

(12) What least number must be added to 15370 to make it a perfect square?

Ans: (b) 6

15370 + 6 = 15376 ⇒ √15376 = 124.

(18) Which of the following is the square of an even number?

Ans: (a) 196

(19) Which of the following is the square of an even number?

Ans: (c) 1369