Finding the Fourth Proportional to 8,581.10, 12,887.49 and 5,139.50

Step by Step Solution

1. Step 1: Write the proportion equation
   8,581.10 : 12,887.49 = 5,139.50 : x
2. Step 2: Convert to fraction form
   8,581.10/12,887.49 = 5,139.50/x
3. Step 3: Cross multiply
   8,581.10x = 12,887.49 × 5,139.50
4. Step 4: Simplify right side
   8,581.10x = 66,235,254.86
5. Step 5: Solve for x
   x = 66,235,254.86/8,581.10
6. Step 6: Final answer
   x = 7,718.74