19/03/2017
PERFECT SQUARE÷
What do we mean by a perfect square??????
A perfect square is a natural no. ,that gives a integer in result when square rooted
Ex÷ 25, √25 = +5 or -5.
How to identify a perfect square ÷
1.A perfect square generally ends with 00,1,4,5,6 and 9, and except these digits in the unit place ,the rest i.e unit palce with 2,3,7,8 are not perfect square.
2.If we add the digits of a perfect square,then the final resultant root digits are 1,4,7 and 9 except these root digits,the number having other digits can't be a perfect square.
3.when a perfect square is devided by 7,it can't leave a remainder of 3,5 or 6.
4.In a perfect square if the unit place digit is 6,then the tenth place digit must be a odd digit.
5.In a perfect square if the unit place digit is 5 then the tenth place digit must be 2
6.in a perfect square even no. Of 0 are present at the end side
7.in a perfect square if the unit digit are 1,4 and 9,then the tenth place digit must be even
If a number satisfies all the above rules then it may be a perfect square,but these rules are right in 90% case ,the rest 10% numbers are exceptional case.
By using these rules we can identify 90% of the perfect square numbers
Example 1 ÷
Let's take a number "65,536"
We have to check whether it is aperfect square or not
1.it ends with 6,so may be
2.root digit is = 6+5+5+3+6=25=2+5=7,so it may be
3.65,536÷7 = leaves a remainder of 2,so it may be
4.unit place 6,tenth palce odd,satisfies
So it is a perfect square.
Example 2 ÷
Let 216
1.unit place 6 ,may be
2.tenth place odd, may be
3.root digit 9,may be
4.when divided by 7 leaves a remainder of 6 ,that doesn't satisfy.
So it is not a perfect square
Example 3 ÷
Exceptional case (only 10% of the total no.)
Let take 184
1.unit place 4 satisfies
2.tenth place even satisfies
3.root digit 4 satisfies
4.when divided by 7 leaves a ramainder of 2 that also satisfies
So it may be a perfect square,but actually it is not a perfect square
So in some cases there are some numbers who satisfy the rules,but they are not actually perfect squares,And the cases are limited to just 10% and the rest 90% must be perfect squares.