Finding the Fourth Proportional to 2,710.55, 4,065.78 and 861.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,710.55 : 4,065.78 = 861.78 : x
2. Step 2: Convert to fraction form
   2,710.55/4,065.78 = 861.78/x
3. Step 3: Cross multiply
   2,710.55x = 4,065.78 × 861.78
4. Step 4: Simplify right side
   2,710.55x = 3,503,807.89
5. Step 5: Solve for x
   x = 3,503,807.89/2,710.55
6. Step 6: Final answer
   x = 1,292.66