Finding the Fourth Proportional to 1,550.41, 2,139.55 and 851.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,550.41 : 2,139.55 = 851.78 : x
2. Step 2: Convert to fraction form
   1,550.41/2,139.55 = 851.78/x
3. Step 3: Cross multiply
   1,550.41x = 2,139.55 × 851.78
4. Step 4: Simplify right side
   1,550.41x = 1,822,429.12
5. Step 5: Solve for x
   x = 1,822,429.12/1,550.41
6. Step 6: Final answer
   x = 1,175.45