Finding the Fourth Proportional to 2,086.72, 3,129.52 and 853.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.72 : 3,129.52 = 853.76 : x
2. Step 2: Convert to fraction form
   2,086.72/3,129.52 = 853.76/x
3. Step 3: Cross multiply
   2,086.72x = 3,129.52 × 853.76
4. Step 4: Simplify right side
   2,086.72x = 2,671,859.00
5. Step 5: Solve for x
   x = 2,671,859.00/2,086.72
6. Step 6: Final answer
   x = 1,280.41