<PRE><B>Question 1198257</B>
**1. Find the Area of the Base**

* The base is an equilateral triangle with side length 12 inches.
* Area of an equilateral triangle = (√3/4) * side² 
* Area of the base = (√3/4) * 12² = 36√3 square inches

**2. Use the Volume Formula**

* Volume of a pyramid = (1/3) * Base Area * Height
* 103.8 = (1/3) * 36√3 * Height
* Height = (103.8 * 3) / (36√3)
* Height ≈ 5 inches

**Therefore, the altitude of the regular triangular pyramid is approximately 5 inches.**
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