First press the 2nd key, then the square root key. Then enter the number 25.85. Then hit Enter. The resulting answer should be something like 5.084289528. Keep in mind that this is not really the exact answer.
Calculators are limited to a specific number of decimal places.
The TI calculator can display no more than 10 places. However, for most purposes, 5.084289528 is a fine approximation for . Now suppose you want to evaluate something like on your calculator. First press the 2nd key, then the square root key. Here things vary a bit based on calculator.