Finding the Fourth Proportional to 13,443.80, 18,549.78 and 8,139.11

Step by Step Solution

1. Step 1: Write the proportion equation
   13,443.80 : 18,549.78 = 8,139.11 : x
2. Step 2: Convert to fraction form
   13,443.80/18,549.78 = 8,139.11/x
3. Step 3: Cross multiply
   13,443.80x = 18,549.78 × 8,139.11
4. Step 4: Simplify right side
   13,443.80x = 150,978,607.15
5. Step 5: Solve for x
   x = 150,978,607.15/13,443.80
6. Step 6: Final answer
   x = 11,230.36