Finding the Fourth Proportional to 1,105.48, 1,524.60 and 685.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.48 : 1,524.60 = 685.78 : x
2. Step 2: Convert to fraction form
   1,105.48/1,524.60 = 685.78/x
3. Step 3: Cross multiply
   1,105.48x = 1,524.60 × 685.78
4. Step 4: Simplify right side
   1,105.48x = 1,045,540.19
5. Step 5: Solve for x
   x = 1,045,540.19/1,105.48
6. Step 6: Final answer
   x = 945.78