Finding the Fourth Proportional to 1,128.18, 1,556.61 and 685.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.18 : 1,556.61 = 685.98 : x
2. Step 2: Convert to fraction form
   1,128.18/1,556.61 = 685.98/x
3. Step 3: Cross multiply
   1,128.18x = 1,556.61 × 685.98
4. Step 4: Simplify right side
   1,128.18x = 1,067,803.33
5. Step 5: Solve for x
   x = 1,067,803.33/1,128.18
6. Step 6: Final answer
   x = 946.48