Finding the Fourth Proportional to 2,585.72, 3,878.76 and 855.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,585.72 : 3,878.76 = 855.56 : x
2. Step 2: Convert to fraction form
   2,585.72/3,878.76 = 855.56/x
3. Step 3: Cross multiply
   2,585.72x = 3,878.76 × 855.56
4. Step 4: Simplify right side
   2,585.72x = 3,318,511.91
5. Step 5: Solve for x
   x = 3,318,511.91/2,585.72
6. Step 6: Final answer
   x = 1,283.40