Finding the Fourth Proportional to 1,128.33, 1,557.12 and 686.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.33 : 1,557.12 = 686.12 : x
2. Step 2: Convert to fraction form
   1,128.33/1,557.12 = 686.12/x
3. Step 3: Cross multiply
   1,128.33x = 1,557.12 × 686.12
4. Step 4: Simplify right side
   1,128.33x = 1,068,374.72
5. Step 5: Solve for x
   x = 1,068,374.72/1,128.33
6. Step 6: Final answer
   x = 946.86