Finding the Fourth Proportional to 12,139.88, 18,200.52 and 3,815.09

Step by Step Solution

1. Step 1: Write the proportion equation
   12,139.88 : 18,200.52 = 3,815.09 : x
2. Step 2: Convert to fraction form
   12,139.88/18,200.52 = 3,815.09/x
3. Step 3: Cross multiply
   12,139.88x = 18,200.52 × 3,815.09
4. Step 4: Simplify right side
   12,139.88x = 69,436,530.84
5. Step 5: Solve for x
   x = 69,436,530.84/12,139.88
6. Step 6: Final answer
   x = 5,719.71