Finding the Fourth Proportional to 1,128.47, 1,556.69 and 686.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.47 : 1,556.69 = 686.07 : x
2. Step 2: Convert to fraction form
   1,128.47/1,556.69 = 686.07/x
3. Step 3: Cross multiply
   1,128.47x = 1,556.69 × 686.07
4. Step 4: Simplify right side
   1,128.47x = 1,067,994.88
5. Step 5: Solve for x
   x = 1,067,994.88/1,128.47
6. Step 6: Final answer
   x = 946.41