Finding the Fourth Proportional to 8,128.98, 12,188.34 and 2,861.10

Step by Step Solution

1. Step 1: Write the proportion equation
   8,128.98 : 12,188.34 = 2,861.10 : x
2. Step 2: Convert to fraction form
   8,128.98/12,188.34 = 2,861.10/x
3. Step 3: Cross multiply
   8,128.98x = 12,188.34 × 2,861.10
4. Step 4: Simplify right side
   8,128.98x = 34,872,059.57
5. Step 5: Solve for x
   x = 34,872,059.57/8,128.98
6. Step 6: Final answer
   x = 4,289.84