Finding the Fourth Proportional to 8,651.76, 12,978.76 and 3,105.72

Step by Step Solution

1. Step 1: Write the proportion equation
   8,651.76 : 12,978.76 = 3,105.72 : x
2. Step 2: Convert to fraction form
   8,651.76/12,978.76 = 3,105.72/x
3. Step 3: Cross multiply
   8,651.76x = 12,978.76 × 3,105.72
4. Step 4: Simplify right side
   8,651.76x = 40,308,394.51
5. Step 5: Solve for x
   x = 40,308,394.51/8,651.76
6. Step 6: Final answer
   x = 4,658.98