Finding the Fourth Proportional to 12,321.71, 18,455.72 and 8,100.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,321.71 : 18,455.72 = 8,100.20 : x
2. Step 2: Convert to fraction form
   12,321.71/18,455.72 = 8,100.20/x
3. Step 3: Cross multiply
   12,321.71x = 18,455.72 × 8,100.20
4. Step 4: Simplify right side
   12,321.71x = 149,495,023.14
5. Step 5: Solve for x
   x = 149,495,023.14/12,321.71
6. Step 6: Final answer
   x = 12,132.65