Finding the Fourth Proportional to 2,086.43, 3,129.57 and 853.47

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.43 : 3,129.57 = 853.47 : x
2. Step 2: Convert to fraction form
   2,086.43/3,129.57 = 853.47/x
3. Step 3: Cross multiply
   2,086.43x = 3,129.57 × 853.47
4. Step 4: Simplify right side
   2,086.43x = 2,670,994.11
5. Step 5: Solve for x
   x = 2,670,994.11/2,086.43
6. Step 6: Final answer
   x = 1,280.18