Finding the Fourth Proportional to 8,978.60, 12,390.80 and 4,945.59

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.60 : 12,390.80 = 4,945.59 : x
2. Step 2: Convert to fraction form
   8,978.60/12,390.80 = 4,945.59/x
3. Step 3: Cross multiply
   8,978.60x = 12,390.80 × 4,945.59
4. Step 4: Simplify right side
   8,978.60x = 61,279,791.84
5. Step 5: Solve for x
   x = 61,279,791.84/8,978.60
6. Step 6: Final answer
   x = 6,825.10