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 1 of 7.
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.
Shalini said:
1 decade ago
15625 we can distributed in two parts
like 156/25 becouse we calculated the sqaure any number were ends digit is 5 the last digit of answer is always 5. now camo to second part of d no. square of 12 is 144and square of 13 is 169. square of 13 is > 156 so that we took 12 now we get "125" is the right ans.
like 156/25 becouse we calculated the sqaure any number were ends digit is 5 the last digit of answer is always 5. now camo to second part of d no. square of 12 is 144and square of 13 is 169. square of 13 is > 156 so that we took 12 now we get "125" is the right ans.
Dipankar said:
1 decade ago
Tricky:for Square root separate them in 2 parts from the right hand side i.e. 1089 like 10/ 89. 1st we hav find out root of last digit 9 is 3. 2nd we need 2 look4 the nearest square of 10 is 3. So your answer come 33.
More: 3249. 1st:32/49. 49's root is 7 & nearest square of 32 is 5 (25). So answer be 57.
More: 3249. 1st:32/49. 49's root is 7 & nearest square of 32 is 5 (25). So answer be 57.
Dinesh kumar said:
1 decade ago
5| 15625
----------
5| 3125
----------
5| 625
----------
5| 125
----------
5| 25
----------
5| 5
----------- So 5*5* 5*5* 5*5 get each one 5*5*5=125.
5
1.5625 after the point we have four(2*2)digit.
So put the point before two digit 1.25 is the answer.
----------
5| 3125
----------
5| 625
----------
5| 125
----------
5| 25
----------
5| 5
----------- So 5*5* 5*5* 5*5 get each one 5*5*5=125.
5
1.5625 after the point we have four(2*2)digit.
So put the point before two digit 1.25 is the answer.
Mouni said:
1 week ago
√1.5625
Step 1. Check the last digit possibility 5 = 5,
Step 2. Strike off the last three digits.
Step 3. The remaining value is close to the perfect square root i.e 5 is nearly √2=4=2.
√1 = 1
Therefore, the result is = 1.25.
Step 1. Check the last digit possibility 5 = 5,
Step 2. Strike off the last three digits.
Step 3. The remaining value is close to the perfect square root i.e 5 is nearly √2=4=2.
√1 = 1
Therefore, the result is = 1.25.
(1)
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.
Shruti said:
1 decade ago
@Dipankar.
In the case of 1089 you found out the root of last digit i.e. 9 but in case of 3249 you did calculate the root of last two digits i.e.49 instead of the last digit only i.e. 9. Isn't it contradicting each other?
In the case of 1089 you found out the root of last digit i.e. 9 but in case of 3249 you did calculate the root of last two digits i.e.49 instead of the last digit only i.e. 9. Isn't it contradicting each other?
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.
Jay said:
9 years ago
From the above explanation We get the answer square root of 15625 = 125.
Now in the question the decimal digits are 4.
So in the answer we should have 4/2 = 2 digits in decimal after point so answer is 1.25.
Now in the question the decimal digits are 4.
So in the answer we should have 4/2 = 2 digits in decimal after point so answer is 1.25.
Swetha said:
6 years ago
Let we know x2 = a.
So, x = √a.
Therefore by referring to all the options with there square;
Let options
A)1.05 * 1.05 = 1.1025
B)1.25 * 1.25 = 1.5625.
So by this, we recognise option B is correct.
So, x = √a.
Therefore by referring to all the options with there square;
Let options
A)1.05 * 1.05 = 1.1025
B)1.25 * 1.25 = 1.5625.
So by this, we recognise option B is correct.
(13)
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