Finding the Fourth Proportional to 1,379.27, 1,903.39 and 789.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.27 : 1,903.39 = 789.80 : x
2. Step 2: Convert to fraction form
   1,379.27/1,903.39 = 789.80/x
3. Step 3: Cross multiply
   1,379.27x = 1,903.39 × 789.80
4. Step 4: Simplify right side
   1,379.27x = 1,503,293.47
5. Step 5: Solve for x
   x = 1,503,293.47/1,379.27
6. Step 6: Final answer
   x = 1,089.92