### Discussion :: Square Root and Cube Root - General Questions (Q.No.4)

4. | 1.5625 = ? |
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Answer: Option B Explanation: 1| 1.5625 = 1.25. |

Varun said: (Jul 24, 2010) | |

We can write it as 15625/10000. 5 power of 6 is 15625 and it becomes 5 power of 6/10 power of 4.. 125/100=> 1.25 |

Abinash said: (Jul 29, 2010) | |

Well I think in the 3rd step it should be something after 22 not 24..yes or no? if 245 then how? |

Deepti said: (Aug 1, 2010) | |

Varun's explanation is easier to under stand. |

Abdul said: (Sep 29, 2010) | |

Can you please tell how 125/100? |

Rajesh said: (Dec 16, 2010) | |

the power 6 and power 4 get cancel. then we have 5 power 3 and 10 power 2. |

SAJITHA said: (Dec 29, 2010) | |

Varun your solution is very helpful. |

Sandeep said: (Jan 25, 2011) | |

Actually, 225 = 15*15 = 1*2 625 = 25*25 = 2*3 1225 = 35*35 = 3*4 So... 15625 = ????? = 12*13 = 12*12 Hence it'll be 125/100 = 1.25 |

Shri said: (Feb 27, 2011) | |

Anyone can explain varun's 3rd step? |

Sakshi said: (Mar 2, 2011) | |

Hi Shri! 5 power of 6 and 10 power of 4 we can write it= 5 square*5 square*5 square/10 square*10 square under root it will bcome 5*5*5/10*10 =125/100 =1.25 |

Shalini said: (Jun 17, 2011) | |

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. |

Abhay said: (Jun 24, 2011) | |

Sakshi...U r the Best!! Awesome... Thnks Too...good |

Rakshit said: (Jul 26, 2011) | |

@Sakshi is this method works for all numbers that has the last digit as 5 ? |

Anila said: (Aug 6, 2011) | |

((5^6)1/2)/((10^4)1/2)=5^3/10^2=5*5*5/10^2=125/10^2=125*10^-2=1.25 |

Arun.g said: (Sep 5, 2011) | |

I'm not understand the answer 1.25 according to me we divided 1.5625 the answers are 1, 22, 245 how 1.25 comes. |

B.sridhar said: (Oct 1, 2011) | |

Shalini explanation is good but the number is different that is 17079 how to calculate please tell me. |

Kiran said: (Oct 27, 2011) | |

Varun explaination is very good. |

Murali said: (Nov 25, 2011) | |

root of 1.5625 = ? We can write it as 15625/10000. =1.5625 = root of 1.5625 = 1.25 |

PAYAL HADKE said: (Dec 12, 2011) | |

VERY APT ANSWER MURLI |

Ranjeet said: (Jan 8, 2012) | |

How instantly get 5 power of 6 = 15625 as explained by Varun initially, is there as short formula please explain any one ? |

Sandhya said: (Mar 29, 2012) | |

sqrt of 1. 5625 = sqrt of [15625/10000]. 15625=125*125 ; 10000=100*100. =125^2 ; =100^2. sqrt of 15625=[125^2]^ (1/2) ; sqrt of 10000=[100^2]^ (1/2). Powers get cancelled, therefore = 125/100. = 1. 25. |

Hari said: (Apr 9, 2012) | |

Hi friends, I can't to understand how to take square root from any number. Could any one explain me please. |

Dipankar said: (Apr 22, 2012) | |

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. |

Krishna Teja said: (Aug 27, 2012) | |

@Dipankar. Thank you very much dude :). |

Kumari said: (Sep 2, 2012) | |

@Dipankar Nice Trick dipankar. Please keep sharing your knowledge..thanks! |

Dinesh Kumar said: (Feb 9, 2013) | |

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. |

Shali said: (Apr 28, 2013) | |

5 | 15625 ---------- 5 | 3125 ---------- 25| 625 ---------- 25| 25 ---------- | 1 5*5*25*25 while taking square root 5*25 = 125 i.e 1.25 decimal after 2 digits. |

Shruti said: (Jun 6, 2013) | |

@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? |

Imran Khan said: (Jul 29, 2013) | |

Let me know how can we understand 22 is to come or 245 in particular steps? |

Lithin said: (Aug 5, 2013) | |

Can anyone please explain the factorization method? |

Dulberg said: (Oct 10, 2013) | |

@Shruti. I think @Dipankar was just trying to give a clue. Personally I find it very useful. It gives you the idea about the figure you should expect. |

Priya said: (Mar 7, 2014) | |

We can write 1.5625 as 15625/10000. So, (125)^2=15625 and (100)^2=10000. So, by taking square root of this it became 125/100 So the answer is 1.25. |

Oshin said: (Apr 1, 2014) | |

Ya its 1.25, one method is. Take last 2 digits 25, and square root of it is 5. And 156 = 12*13, we must take smaller number, 12. So its 125 and add decimal, then its 1.25. |

Sai Prasanna said: (Jul 7, 2014) | |

We can easily calculate by given options i.e., 1.25 * 1.25 = 1.5625. |

Vivek Wadhawan said: (Aug 30, 2014) | |

@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. |

Amisha said: (Sep 7, 2014) | |

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. |

Raj said: (Sep 23, 2014) | |

Can you explain in more simpler manner? |

Parthkushte said: (Jan 9, 2015) | |

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). |

Rakshit said: (Feb 27, 2015) | |

In main solution there is 225 instead of 245 might be. |

Anil said: (Apr 21, 2015) | |

Can any one tell why 22 and 245 came in solution they give in the explanation? |

Prashant said: (May 18, 2015) | |

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. |

Sheetal said: (Jul 30, 2015) | |

Thanks for the simple explanations. Please include shortcut tricks along with the explanations. |

Rkcckr said: (Aug 16, 2015) | |

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. |

Som said: (Dec 29, 2015) | |

Remember trick, in 15625 last two digits can be obtained by multiplying 5*5. Now 156 can be obtained by multi 12*13. So answer will be 125 now put decimal accordingly. |

Siva said: (Feb 23, 2016) | |

1.25 *1.25. If the last digits ends with 5 always in both the sides multiply 5*5. Then in the first digit add one number. 12 + 1 = 13. Now multiply 12*13 = 156. This method will be more easy. |

Jay said: (Mar 10, 2016) | |

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. |

Laks said: (May 25, 2016) | |

@Shalini and @Dipankar Your method is Right. |

Rudh said: (Jul 18, 2016) | |

@Sandhya. Thank you so much. |

Kiran said: (Aug 8, 2016) | |

Thank you friends. It is easy to understand now. |

Sidhu said: (Jan 21, 2018) | |

@ALL. Very simple short cut 1+5+6+2+5 = 8 [A]. 1.05(1+5)=6. [B]. 1.25 (1+2+5)=8. [C]. 1.45(1+4+5=10)=(1+0)=1. [D]. 1.55(1+5+5=11)=(1+1)=)2. So the answer is B. |

Rahul said: (Dec 1, 2018) | |

@Varun The 3rd step is; {(5*5*5*5*5*5)/10*10*10*10)}, = 5*5*5/10*10, = 125/100, = 1.25. |

Hareesh said: (Jan 17, 2019) | |

(15625/10000)^0.5. = (15625^0.5)/{10^(4/2)}, = {(5*5*5)(5*5*5*)}^0.5/(10^2). = 125/100, = 1.25. |

Pranitha said: (Feb 11, 2019) | |

(15625/10000) ^1/2. We have to cancel the above 2values. Then we get (25/16) ^1/2, = 5/4. The ans is 1.25. |

Rahul said: (May 15, 2019) | |

@Sidhu. How is 1+5+6+2+5=8? |

Honnu said: (Jun 6, 2019) | |

@Sidhu. 1+5+6+2+5=19, How it will be 8? Please explain. |

Karthick said: (Jun 14, 2019) | |

Thanks for explaining the answer @Varun. |

Swetha said: (Aug 23, 2019) | |

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. |

Bhavani said: (Jan 25, 2020) | |

It's very clear for understanding. Thank you @Swetha. |

Sreehari said: (Jan 27, 2021) | |

How to get 245? |

Wokete Saeed said: (Dec 20, 2021) | |

Thanks for explaining @Dinesh Kumar. |

JUBANLAK SUTNGA said: (Sep 10, 2022) | |

= 15625/10000, = 25/16, = √5^2/4^2, = 5/4, = 1.25. It's the easiest way to find the answer. |

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