Finding the Fourth Proportional to 8,439.35, 12,661.59 and 5,978.93

Step by Step Solution

1. Step 1: Write the proportion equation
   8,439.35 : 12,661.59 = 5,978.93 : x
2. Step 2: Convert to fraction form
   8,439.35/12,661.59 = 5,978.93/x
3. Step 3: Cross multiply
   8,439.35x = 12,661.59 × 5,978.93
4. Step 4: Simplify right side
   8,439.35x = 75,702,760.30
5. Step 5: Solve for x
   x = 75,702,760.30/8,439.35
6. Step 6: Final answer
   x = 8,970.21