Finding the Fourth Proportional to 2,587.78, 3,878.17 and 1,855.75

Step by Step Solution

1. Step 1: Write the proportion equation
   2,587.78 : 3,878.17 = 1,855.75 : x
2. Step 2: Convert to fraction form
   2,587.78/3,878.17 = 1,855.75/x
3. Step 3: Cross multiply
   2,587.78x = 3,878.17 × 1,855.75
4. Step 4: Simplify right side
   2,587.78x = 7,196,913.98
5. Step 5: Solve for x
   x = 7,196,913.98/2,587.78
6. Step 6: Final answer
   x = 2,781.12