Finding the Fourth Proportional to 21,851.98, 30,155.56 and 12,420.54

Step by Step Solution

1. Step 1: Write the proportion equation
   21,851.98 : 30,155.56 = 12,420.54 : x
2. Step 2: Convert to fraction form
   21,851.98/30,155.56 = 12,420.54/x
3. Step 3: Cross multiply
   21,851.98x = 30,155.56 × 12,420.54
4. Step 4: Simplify right side
   21,851.98x = 374,548,308.15
5. Step 5: Solve for x
   x = 374,548,308.15/21,851.98
6. Step 6: Final answer
   x = 17,140.25