Finding the Fourth Proportional to 1,379.52, 1,912.32 and 1,291.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.52 : 1,912.32 = 1,291.20 : x
2. Step 2: Convert to fraction form
   1,379.52/1,912.32 = 1,291.20/x
3. Step 3: Cross multiply
   1,379.52x = 1,912.32 × 1,291.20
4. Step 4: Simplify right side
   1,379.52x = 2,469,187.58
5. Step 5: Solve for x
   x = 2,469,187.58/1,379.52
6. Step 6: Final answer
   x = 1,789.89