Finding the Fourth Proportional to 1,128.12, 1,556.88 and 686.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.12 : 1,556.88 = 686.04 : x
2. Step 2: Convert to fraction form
   1,128.12/1,556.88 = 686.04/x
3. Step 3: Cross multiply
   1,128.12x = 1,556.88 × 686.04
4. Step 4: Simplify right side
   1,128.12x = 1,068,081.96
5. Step 5: Solve for x
   x = 1,068,081.96/1,128.12
6. Step 6: Final answer
   x = 946.78