Finding the Fourth Proportional to 8,730.38, 13,081.40 and 8,406.78

Step by Step Solution

1. Step 1: Write the proportion equation
   8,730.38 : 13,081.40 = 8,406.78 : x
2. Step 2: Convert to fraction form
   8,730.38/13,081.40 = 8,406.78/x
3. Step 3: Cross multiply
   8,730.38x = 13,081.40 × 8,406.78
4. Step 4: Simplify right side
   8,730.38x = 109,972,451.89
5. Step 5: Solve for x
   x = 109,972,451.89/8,730.38
6. Step 6: Final answer
   x = 12,596.53