Again received an overwhelming number of answers to this puzzle. People who answered it correctly included Pratik Poddar, Anant Aggarwal, Siddharth Mulherkar, Suman Saraf, P R Kumar and Amit Mittal. The puzzle had a simple trick to it, which is that the phrase we are trying to get to is embedded itself within the phrase.
I am reproducing the answer from Pratik Poddar.
Lets say that the value is x.
sqrt (12+x) = x
x^2 – x – 12 = 0
(x-4)(x+3) = 0
x = 4 (since x>0)
Hope you all enjoyed the puzzle!