It is a good idea to get familiar with the operation of your calculator. If you're going to use on-line resources to work problems like this, you can make use of any of several good on-line calculators. Google and Bing search boxes will do calculations for you while observing all the rules of the Order of Operations.
The result of this computation is a number that begins 2.56.... Since the hundredths digit is more than 4, the tenths digit is rounded to the next higher value, from 5 to 6.
Rounded to tenths, 2.1√1.488 = 2.6
