A fraction is written in terms of two parts: the number on top is called the numerator and the number on the bottom is called the denominator. We can use the division method to solve this question. To get a decimal, simply divide the numerator 139 by the denominator 40:
139 (numerator) ÷ 40 (denominator) = 3.48
As a result, you get 3.48 as your answer when you convert 3 19/40 (or 139/40) to a decimal.