Finding the Fourth Proportional to 6,420.05, 8,858.71 and 3,900.83

Step by Step Solution

1. Step 1: Write the proportion equation
   6,420.05 : 8,858.71 = 3,900.83 : x
2. Step 2: Convert to fraction form
   6,420.05/8,858.71 = 3,900.83/x
3. Step 3: Cross multiply
   6,420.05x = 8,858.71 × 3,900.83
4. Step 4: Simplify right side
   6,420.05x = 34,556,321.73
5. Step 5: Solve for x
   x = 34,556,321.73/6,420.05
6. Step 6: Final answer
   x = 5,382.56