Finding the Fourth Proportional to 1,385.89, 2,078.83 and 728.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.89 : 2,078.83 = 728.87 : x
2. Step 2: Convert to fraction form
   1,385.89/2,078.83 = 728.87/x
3. Step 3: Cross multiply
   1,385.89x = 2,078.83 × 728.87
4. Step 4: Simplify right side
   1,385.89x = 1,515,196.82
5. Step 5: Solve for x
   x = 1,515,196.82/1,385.89
6. Step 6: Final answer
   x = 1,093.30