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 129 by the denominator 14:
129 (numerator) ÷ 14 (denominator) = 9.21
As a result, you get 9.21 as your answer when you convert 3 87/14 (or 129/14) to a decimal.