Finding the Fourth Proportional to 2,551.76, 3,827.61 and 820.39

Step by Step Solution

1. Step 1: Write the proportion equation
   2,551.76 : 3,827.61 = 820.39 : x
2. Step 2: Convert to fraction form
   2,551.76/3,827.61 = 820.39/x
3. Step 3: Cross multiply
   2,551.76x = 3,827.61 × 820.39
4. Step 4: Simplify right side
   2,551.76x = 3,140,123.40
5. Step 5: Solve for x
   x = 3,140,123.40/2,551.76
6. Step 6: Final answer
   x = 1,230.57