Finding the Fourth Proportional to 1,128.90, 1,684.22 and 1,005.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.90 : 1,684.22 = 1,005.78 : x
2. Step 2: Convert to fraction form
   1,128.90/1,684.22 = 1,005.78/x
3. Step 3: Cross multiply
   1,128.90x = 1,684.22 × 1,005.78
4. Step 4: Simplify right side
   1,128.90x = 1,693,954.79
5. Step 5: Solve for x
   x = 1,693,954.79/1,128.90
6. Step 6: Final answer
   x = 1,500.54