Finding the Fourth Proportional to 5,116.39, 7,680.28 and 2,650.55

Step by Step Solution

1. Step 1: Write the proportion equation
   5,116.39 : 7,680.28 = 2,650.55 : x
2. Step 2: Convert to fraction form
   5,116.39/7,680.28 = 2,650.55/x
3. Step 3: Cross multiply
   5,116.39x = 7,680.28 × 2,650.55
4. Step 4: Simplify right side
   5,116.39x = 20,356,966.15
5. Step 5: Solve for x
   x = 20,356,966.15/5,116.39
6. Step 6: Final answer
   x = 3,978.78