Finding the Fourth Proportional to 8,906.23, 12,289.98 and 5,128.51

Step by Step Solution

1. Step 1: Write the proportion equation
   8,906.23 : 12,289.98 = 5,128.51 : x
2. Step 2: Convert to fraction form
   8,906.23/12,289.98 = 5,128.51/x
3. Step 3: Cross multiply
   8,906.23x = 12,289.98 × 5,128.51
4. Step 4: Simplify right side
   8,906.23x = 63,029,285.33
5. Step 5: Solve for x
   x = 63,029,285.33/8,906.23
6. Step 6: Final answer
   x = 7,076.99