Finding the Fourth Proportional to 13,128.21, 18,105.12 and 8,411.58

Step by Step Solution

1. Step 1: Write the proportion equation
   13,128.21 : 18,105.12 = 8,411.58 : x
2. Step 2: Convert to fraction form
   13,128.21/18,105.12 = 8,411.58/x
3. Step 3: Cross multiply
   13,128.21x = 18,105.12 × 8,411.58
4. Step 4: Simplify right side
   13,128.21x = 152,292,665.29
5. Step 5: Solve for x
   x = 152,292,665.29/13,128.21
6. Step 6: Final answer
   x = 11,600.41