Finding the Fourth Proportional to 842.78, 1,162.60 and 685.59

Step by Step Solution

1. Step 1: Write the proportion equation
   842.78 : 1,162.60 = 685.59 : x
2. Step 2: Convert to fraction form
   842.78/1,162.60 = 685.59/x
3. Step 3: Cross multiply
   842.78x = 1,162.60 × 685.59
4. Step 4: Simplify right side
   842.78x = 797,060.86
5. Step 5: Solve for x
   x = 797,060.86/842.78
6. Step 6: Final answer
   x = 945.75