1. Squares and Square Roots
Revision
1) =169
1)169 is the square of 13,and 13 is the square root of 169.
2) =225
2)….. is the square of 15,and ……is the square root of 225.
225 15 ü

2. ü Finding square root of given number as following 205 2 +2 4 20 25 -440 +0
020
-00
2025
-2025
405 +5
410
0000
Square root of is 205 ü

3. Square roots of positive numbers
It is customary not to write ‘+’sign before a positive number.Like +10=10.
4*4=16,4 is the square root of 16.
Also -4*-4=16,-4 is the square root of 16.
Thus 4&-4 are the two square roots of 16.
EVERY POSITIVE NUMBER HAS TWO SQUARE ROOTS.
THESE SQUARE ROOTS ARE OPPOSITE NUMBER OF EACH OTHER.

4. Writing and Reading a square root
‘Õ’
This sign refer to a square root
‘Õ’
This sign also refer to a positive square root Õ’
‘ -
This sign refer to a negative square root
Read as ‘positive square root of 225’
Read as ‘negative square root of 144’ ü

5. Perfect square numbers
A number which is the square of an integer is called a perfect square.
Ex-4,9,16,25,36,49,225,625,576 etc.
Not Perfect square numbers
The number which are not the squares of an any integer are called not perfect square numbers ex-2,3,5,6,7,8,10 etc. ü

6. The square root of a non-perfect square number
…….. 4 +4 84
887 +7
8942
89441
89442
-16
0400
- 336
006400
- 6209
019100
032159
=4.4721… and = ü

7. The approximate value of the square root of a non perfect square number
=4.4721…
=4.47(Approximate value up to the second decimal place)
=4.5 (Approximate value up to the first decimal place)
The quotient …………… is written as 3.58
In a non terminating recurring decimal,the recurring digits are marked with a line drawn above them ü

8. Shri : Bihani R. J. Std : 7 & 8 th School Name : Smt: K. N. K. P. K. V
Shri : Bihani R.J. Std : 7 & 8 th School Name : Smt: K.N.K.P.K.V. Satral