Finding the Fourth Proportional to 12,139.25, 18,209.88 and 3,820.55

Step by Step Solution

1. Step 1: Write the proportion equation
   12,139.25 : 18,209.88 = 3,820.55 : x
2. Step 2: Convert to fraction form
   12,139.25/18,209.88 = 3,820.55/x
3. Step 3: Cross multiply
   12,139.25x = 18,209.88 × 3,820.55
4. Step 4: Simplify right side
   12,139.25x = 69,571,665.98
5. Step 5: Solve for x
   x = 69,571,665.98/12,139.25
6. Step 6: Final answer
   x = 5,731.14