Finding the Fourth Proportional to 2,231.07, 3,078.12 and 1,391.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,231.07 : 3,078.12 = 1,391.10 : x
2. Step 2: Convert to fraction form
   2,231.07/3,078.12 = 1,391.10/x
3. Step 3: Cross multiply
   2,231.07x = 3,078.12 × 1,391.10
4. Step 4: Simplify right side
   2,231.07x = 4,281,972.73
5. Step 5: Solve for x
   x = 4,281,972.73/2,231.07
6. Step 6: Final answer
   x = 1,919.25