Aptitude - Square Root and Cube Root - Discussion

For better result you can consider it as follow:

The square root of 81 = 9*9 = 9.

So, the square root of 80 should be less then 9 lets guess it as 8.80.

Same way the square root of 4 = 2*2.

We can guest square root of 5 should be greater then 2 lets say it is 2.25.

Now 8.80+6*2.25 = 8.80+13.50 = 22.30.

Choose the nearest answer from our answer which is 22.35.

So answer = 22.35.

This is not accurate method this can be only use when you have very less time.

Easy way to find R5 value.

2 square is 4.
3 square is 9.
So, find the number between 2 and 3.we choose 2 because 2 square is 4 less than 5.
5/2=2.5.

Average between 2 and 2.5.
2 + 2.5/2 = 4.5/2 = 2.235.
So, the R5 value is 2.235.

Sr 80 + 6 Sr 5.

It means that Sr 16 * 5 + 6 Sr 5.
=> 4 Sr 5 + 6 Sr 5.

Then simplify 10 Sr 5 = 10* sr 5.

Sr 5 is = 2.235 * 2.235.
10 * 2.232 = 22.35.

Hello zee.

You are right. But we know R5 value. For higher root values above explanation process is must.

Make square of 3R5 square of 3 = 9 & square of R5 = R5*R5 = 5.

This is the answer and meaning of 3R5.

Easiest way is;

8√5=1788/100.
=> (10/8)*8√5 = (1788/100) * (10/8) = 223.5/10 = 22.35.

Please tell me what is the meaning of 3 root 5? Is it 125, means cube of 5. I am little confused.

I don't know how to find roots for long numbers like 34567 can you please tell me that.

If 35 + 125 = 17.88, then what will be the value of 80 + 65? Please explain.

I don't understand this sum clearly. Can anyone help me to understand this?