Finding the Fourth Proportional to 6,389.78, 8,818.00 and 3,557.31

Step by Step Solution

1. Step 1: Write the proportion equation
   6,389.78 : 8,818.00 = 3,557.31 : x
2. Step 2: Convert to fraction form
   6,389.78/8,818.00 = 3,557.31/x
3. Step 3: Cross multiply
   6,389.78x = 8,818.00 × 3,557.31
4. Step 4: Simplify right side
   6,389.78x = 31,368,350.69
5. Step 5: Solve for x
   x = 31,368,350.69/6,389.78
6. Step 6: Final answer
   x = 4,909.14