Finding the Fourth Proportional to 12,406.50, 17,128.89 and 8,628.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,406.50 : 17,128.89 = 8,628.30 : x
2. Step 2: Convert to fraction form
   12,406.50/17,128.89 = 8,628.30/x
3. Step 3: Cross multiply
   12,406.50x = 17,128.89 × 8,628.30
4. Step 4: Simplify right side
   12,406.50x = 147,793,201.59
5. Step 5: Solve for x
   x = 147,793,201.59/12,406.50
6. Step 6: Final answer
   x = 11,912.56