Finding the Fourth Proportional to 2,586.88, 3,880.38 and 855.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,586.88 : 3,880.38 = 855.50 : x
2. Step 2: Convert to fraction form
   2,586.88/3,880.38 = 855.50/x
3. Step 3: Cross multiply
   2,586.88x = 3,880.38 × 855.50
4. Step 4: Simplify right side
   2,586.88x = 3,319,665.09
5. Step 5: Solve for x
   x = 3,319,665.09/2,586.88
6. Step 6: Final answer
   x = 1,283.27