Learn Class 8 Math - Squares and Square Roots

Introduction to Square Numbers

A natural number m with the formula n/2 is a square number if n is also a natural number.

Example: 1, 4, 9, 16, and 25.

Calculating the square of a number

If n is a number, then its square can be expressed as n * n = n square

E.g. The square of six is equal to 6*6 = 36

Using identity to find the square of a number

You can easily find the squares of numbers with two or more digits by summing two numbers.

For example: 23 square = (20 + 3) 2 = 20 (20+3)+3(20+3) = 20 square+20×3 + 20×3 + 32 = 400 + 60 + 60 + 9 = 529

Properties of the Square Number:

  • There's no perfect square if the number ends in 2, 3, 7, or 8.
  • Zeros on an odd digit don't make a perfect square.
  • Even numbers squared equal an even number.
  • When a number is odd, its square is odd.
  • Squares of proper fractions are smaller than their fractional parts.
  • Each natural number n has the formula [(n + 1)2 - n2} = {(n + 1) + n}.
  • Natural number n 2 = sum of first n odd numbers.
  • The triplet consisting of m, n, p is called a Pythagorean triplet if (m2 + n2) = p2.
  • The Pythagorean triplet is formed by (2m, m2 – 1, m2 + 1) for every natural number m > 1.

Learning Videos for 8th Grade Math - Squares and Square Roots

Squares and Square Roots Sample Questions for Class 8

Question 1

Which integer is closest in value to sqrt 15?
A. 2
B. 3
C. 4
D. 5

Question 2

Which of these is the closest approximation for sqrt(74/31?
A. 1.54510
B. 2.0000
C. 1.05450
D. 1.54502

Question 3

Which of these is the closest approximation for sqrt(55)/7?
A. 1.05946
B. 1.05950
C. 1.05945
D. 1.59456

Question 4

Choose the best answer.sqrt(5) is between which two numbers?
A. 0 and 0.5
B. 0 and 1
C. 1 and 2
D. 2 and 3

Question 5

Choose the number that is irrational.
A. sqrt3969
B. sqrt289/2500
C. sqrt(289/250
D. sqrt9801