The formula for the arithmetic mean is:
(mean) = (sum of terms) / (number of terms)
In this case, we know that the mean is 29 and there are three terms (25, 29, and x). So, we can write:
29 = (25 + 29 + x) / 3
Multiplying both sides by 3, we get:
87 = 25 + 29 + x
Simplifying, we get:
87 = 54 + x
Subtracting 54 from both sides, we get:
x = 33
Therefore, the missing number is x = 33.