Finding the Fourth Proportional to 1,379.39, 1,903.56 and 789.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,379.39 : 1,903.56 = 789.89 : x
2. Step 2: Convert to fraction form
   1,379.39/1,903.56 = 789.89/x
3. Step 3: Cross multiply
   1,379.39x = 1,903.56 × 789.89
4. Step 4: Simplify right side
   1,379.39x = 1,503,603.01
5. Step 5: Solve for x
   x = 1,503,603.01/1,379.39
6. Step 6: Final answer
   x = 1,090.05