Finding the Fourth Proportional to 1,289.89, 1,778.71 and 1,103.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,289.89 : 1,778.71 = 1,103.99 : x
2. Step 2: Convert to fraction form
   1,289.89/1,778.71 = 1,103.99/x
3. Step 3: Cross multiply
   1,289.89x = 1,778.71 × 1,103.99
4. Step 4: Simplify right side
   1,289.89x = 1,963,678.05
5. Step 5: Solve for x
   x = 1,963,678.05/1,289.89
6. Step 6: Final answer
   x = 1,522.36