Finding the Fourth Proportional to 5,406.89, 8,139.02 and 3,857.61

Step by Step Solution

1. Step 1: Write the proportion equation
   5,406.89 : 8,139.02 = 3,857.61 : x
2. Step 2: Convert to fraction form
   5,406.89/8,139.02 = 3,857.61/x
3. Step 3: Cross multiply
   5,406.89x = 8,139.02 × 3,857.61
4. Step 4: Simplify right side
   5,406.89x = 31,397,145.65
5. Step 5: Solve for x
   x = 31,397,145.65/5,406.89
6. Step 6: Final answer
   x = 5,806.88