Finding the Fourth Proportional to 1,078.42, 1,610.32 and 856.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,078.42 : 1,610.32 = 856.55 : x
2. Step 2: Convert to fraction form
   1,078.42/1,610.32 = 856.55/x
3. Step 3: Cross multiply
   1,078.42x = 1,610.32 × 856.55
4. Step 4: Simplify right side
   1,078.42x = 1,379,321.48
5. Step 5: Solve for x
   x = 1,379,321.48/1,078.42
6. Step 6: Final answer
   x = 1,279.02