Finding the Fourth Proportional to 1,989.78, 2,745.90 and 1,105.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,989.78 : 2,745.90 = 1,105.62 : x
2. Step 2: Convert to fraction form
   1,989.78/2,745.90 = 1,105.62/x
3. Step 3: Cross multiply
   1,989.78x = 2,745.90 × 1,105.62
4. Step 4: Simplify right side
   1,989.78x = 3,035,921.96
5. Step 5: Solve for x
   x = 3,035,921.96/1,989.78
6. Step 6: Final answer
   x = 1,525.76