The square root of 5 is an irrational number because the square root is ? x ? = _. So ? x ? = 5? Also, everything besides the square root of 2, 3, 5, 7, 8, 10, Pi, and lots of other numbers can be expressed as a fraction and a decimal. However, irrational numbers are never ending. For example, the square root of 5 goes on for 2.2360679774997896964091736687313... and it goes on forever.