Finding the Fourth Proportional to 1,379.31, 1,904.10 and 789.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.31 : 1,904.10 = 789.73 : x
2. Step 2: Convert to fraction form
   1,379.31/1,904.10 = 789.73/x
3. Step 3: Cross multiply
   1,379.31x = 1,904.10 × 789.73
4. Step 4: Simplify right side
   1,379.31x = 1,503,724.89
5. Step 5: Solve for x
   x = 1,503,724.89/1,379.31
6. Step 6: Final answer
   x = 1,090.20