Finding the Fourth Proportional to 12,940.78, 19,406.39 and 4,618.57

Step by Step Solution

1. Step 1: Write the proportion equation
   12,940.78 : 19,406.39 = 4,618.57 : x
2. Step 2: Convert to fraction form
   12,940.78/19,406.39 = 4,618.57/x
3. Step 3: Cross multiply
   12,940.78x = 19,406.39 × 4,618.57
4. Step 4: Simplify right side
   12,940.78x = 89,629,650.54
5. Step 5: Solve for x
   x = 89,629,650.54/12,940.78
6. Step 6: Final answer
   x = 6,926.14