Finding the Fourth Proportional to 12,450.31, 18,677.69 and 4,128.78

Step by Step Solution

1. Step 1: Write the proportion equation
   12,450.31 : 18,677.69 = 4,128.78 : x
2. Step 2: Convert to fraction form
   12,450.31/18,677.69 = 4,128.78/x
3. Step 3: Cross multiply
   12,450.31x = 18,677.69 × 4,128.78
4. Step 4: Simplify right side
   12,450.31x = 77,116,072.92
5. Step 5: Solve for x
   x = 77,116,072.92/12,450.31
6. Step 6: Final answer
   x = 6,193.91