Finding the Fourth Proportional to 1,385.78, 1,911.62 and 854.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.78 : 1,911.62 = 854.77 : x
2. Step 2: Convert to fraction form
   1,385.78/1,911.62 = 854.77/x
3. Step 3: Cross multiply
   1,385.78x = 1,911.62 × 854.77
4. Step 4: Simplify right side
   1,385.78x = 1,633,986.37
5. Step 5: Solve for x
   x = 1,633,986.37/1,385.78
6. Step 6: Final answer
   x = 1,179.11