Finding the Fourth Proportional to 10,900.31, 16,356.38 and 8,439.94

Step by Step Solution

1. Step 1: Write the proportion equation
   10,900.31 : 16,356.38 = 8,439.94 : x
2. Step 2: Convert to fraction form
   10,900.31/16,356.38 = 8,439.94/x
3. Step 3: Cross multiply
   10,900.31x = 16,356.38 × 8,439.94
4. Step 4: Simplify right side
   10,900.31x = 138,046,782.73
5. Step 5: Solve for x
   x = 138,046,782.73/10,900.31
6. Step 6: Final answer
   x = 12,664.48