Finding the Fourth Proportional to 12,579.72, 18,868.42 and 4,258.78

Step by Step Solution

1. Step 1: Write the proportion equation
   12,579.72 : 18,868.42 = 4,258.78 : x
2. Step 2: Convert to fraction form
   12,579.72/18,868.42 = 4,258.78/x
3. Step 3: Cross multiply
   12,579.72x = 18,868.42 × 4,258.78
4. Step 4: Simplify right side
   12,579.72x = 80,356,486.25
5. Step 5: Solve for x
   x = 80,356,486.25/12,579.72
6. Step 6: Final answer
   x = 6,387.78