Finding the Fourth Proportional to 1,378.83, 1,903.22 and 789.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.83 : 1,903.22 = 789.77 : x
2. Step 2: Convert to fraction form
   1,378.83/1,903.22 = 789.77/x
3. Step 3: Cross multiply
   1,378.83x = 1,903.22 × 789.77
4. Step 4: Simplify right side
   1,378.83x = 1,503,092.59
5. Step 5: Solve for x
   x = 1,503,092.59/1,378.83
6. Step 6: Final answer
   x = 1,090.12