Finding the Fourth Proportional to 8,978.64, 12,390.41 and 4,945.39

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.64 : 12,390.41 = 4,945.39 : x
2. Step 2: Convert to fraction form
   8,978.64/12,390.41 = 4,945.39/x
3. Step 3: Cross multiply
   8,978.64x = 12,390.41 × 4,945.39
4. Step 4: Simplify right side
   8,978.64x = 61,275,384.98
5. Step 5: Solve for x
   x = 61,275,384.98/8,978.64
6. Step 6: Final answer
   x = 6,824.58