Finding the Fourth Proportional to 12,261.69, 18,390.78 and 3,940.65

Step by Step Solution

1. Step 1: Write the proportion equation
   12,261.69 : 18,390.78 = 3,940.65 : x
2. Step 2: Convert to fraction form
   12,261.69/18,390.78 = 3,940.65/x
3. Step 3: Cross multiply
   12,261.69x = 18,390.78 × 3,940.65
4. Step 4: Simplify right side
   12,261.69x = 72,471,627.21
5. Step 5: Solve for x
   x = 72,471,627.21/12,261.69
6. Step 6: Final answer
   x = 5,910.41