Finding the Fourth Proportional to 1,128.72, 1,689.54 and 869.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.72 : 1,689.54 = 869.73 : x
2. Step 2: Convert to fraction form
   1,128.72/1,689.54 = 869.73/x
3. Step 3: Cross multiply
   1,128.72x = 1,689.54 × 869.73
4. Step 4: Simplify right side
   1,128.72x = 1,469,443.62
5. Step 5: Solve for x
   x = 1,469,443.62/1,128.72
6. Step 6: Final answer
   x = 1,301.87