Finding the Fourth Proportional to 3,906.60, 5,861.10 and 3,085.20

Step by Step Solution

1. Step 1: Write the proportion equation
   3,906.60 : 5,861.10 = 3,085.20 : x
2. Step 2: Convert to fraction form
   3,906.60/5,861.10 = 3,085.20/x
3. Step 3: Cross multiply
   3,906.60x = 5,861.10 × 3,085.20
4. Step 4: Simplify right side
   3,906.60x = 18,082,665.72
5. Step 5: Solve for x
   x = 18,082,665.72/3,906.60
6. Step 6: Final answer
   x = 4,628.75