Aptitude - Square Root and Cube Root - Discussion
Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 4)
4.
1.5625 = ?
Answer: Option
Explanation:
1|1.5625( 1.25
|1
|-------
22| 56
| 44
|-------
245| 1225
| 1225
|-------
| X
|-------
1.5625 = 1.25.
Discussion:
62 comments Page 3 of 7.
Rkcckr said:
1 decade ago
1.5625 = 15625/1000.
N Numerator = 5^2*5^2*5^2.
D Denominator = 10^2*10^2.
Square root of N/D = 5*5*5/10*10 = 125/100 = 1.25.
N Numerator = 5^2*5^2*5^2.
D Denominator = 10^2*10^2.
Square root of N/D = 5*5*5/10*10 = 125/100 = 1.25.
Sheetal said:
1 decade ago
Thanks for the simple explanations. Please include shortcut tricks along with the explanations.
(1)
Prashant said:
1 decade ago
1.25
---------------
1*1| 1.5625
+1| 1
----------------
22*2|056
+2|044
|-
----------------
245*5|1225
1225
--------------
0000
So answer is 1.25.
So that is the region, why we take 22 and 245.
---------------
1*1| 1.5625
+1| 1
----------------
22*2|056
+2|044
|-
----------------
245*5|1225
1225
--------------
0000
So answer is 1.25.
So that is the region, why we take 22 and 245.
Anil said:
1 decade ago
Can any one tell why 22 and 245 came in solution they give in the explanation?
Rakshit said:
1 decade ago
In main solution there is 225 instead of 245 might be.
Parthkushte said:
1 decade ago
Whenever a sq.rt. ends with "25"(1.56'25'), the last digit of root is always "5"(1.25).
The other 'digits can be found by this method: '12'X'13' = '156('1.56'25).
The other 'digits can be found by this method: '12'X'13' = '156('1.56'25).
Raj said:
1 decade ago
Can you explain in more simpler manner?
Amisha said:
1 decade ago
sqrt(15625/10000)
Now for 15625, separate into 156 and 25.
For 156, divide into two consecutive number i.e 12*13 and choose least number i.e. "12".
For 25, square root is "5".
Now combine both i.e. 12 and 5 which makes "125".
Now, 125/100 gives 1.25.
This is true for any which can fulfill the criteria i.e.
1. Consecutive number and choosing lower of both.
2. Last 2 digits 25.
This method is best when you know that the number is a perfect square.
Now for 15625, separate into 156 and 25.
For 156, divide into two consecutive number i.e 12*13 and choose least number i.e. "12".
For 25, square root is "5".
Now combine both i.e. 12 and 5 which makes "125".
Now, 125/100 gives 1.25.
This is true for any which can fulfill the criteria i.e.
1. Consecutive number and choosing lower of both.
2. Last 2 digits 25.
This method is best when you know that the number is a perfect square.
Vivek Wadhawan said:
1 decade ago
@Dipankar.
Your trick is good but didn't work for square of n. O whose digit ends with 7.
Let me give an example.
77^2 = 5929. That means acc to your trick sqrt of 5929 should be 73. Where it fails.
Another ex :- 27^2.
Your trick is good but didn't work for square of n. O whose digit ends with 7.
Let me give an example.
77^2 = 5929. That means acc to your trick sqrt of 5929 should be 73. Where it fails.
Another ex :- 27^2.
Sai prasanna said:
1 decade ago
We can easily calculate by given options i.e.,
1.25 * 1.25 = 1.5625.
1.25 * 1.25 = 1.5625.
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