Finding the Fourth Proportional to 1,379.35, 1,903.47 and 789.85

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.35 : 1,903.47 = 789.85 : x
2. Step 2: Convert to fraction form
   1,379.35/1,903.47 = 789.85/x
3. Step 3: Cross multiply
   1,379.35x = 1,903.47 × 789.85
4. Step 4: Simplify right side
   1,379.35x = 1,503,455.78
5. Step 5: Solve for x
   x = 1,503,455.78/1,379.35
6. Step 6: Final answer
   x = 1,089.97