Finding the Fourth Proportional to 13,387.21, 18,480.78 and 9,411.73

Step by Step Solution

1. Step 1: Write the proportion equation
   13,387.21 : 18,480.78 = 9,411.73 : x
2. Step 2: Convert to fraction form
   13,387.21/18,480.78 = 9,411.73/x
3. Step 3: Cross multiply
   13,387.21x = 18,480.78 × 9,411.73
4. Step 4: Simplify right side
   13,387.21x = 173,936,111.55
5. Step 5: Solve for x
   x = 173,936,111.55/13,387.21
6. Step 6: Final answer
   x = 12,992.71