Kaplan Mock Vol 2 - Exam 1 - Q#76

hey guys - in kaplan’s second mock exam book exam 1, question 76:

The question asks for the revenue growth rate from 2014 - 2016, given 2016 & 2014 values. My logic to calc growth rate is to find the % change over the period ( 2016/2014 - 1) although the answer raises it to the 1/2:: answer = (2016/2014)^.5 -1.

Just trying to understand the logic of raising it to .5

thanks