Finding the Fourth Proportional to 3,861.30, 5,781.42 and 2,815.86

Step by Step Solution

1. Step 1: Write the proportion equation
   3,861.30 : 5,781.42 = 2,815.86 : x
2. Step 2: Convert to fraction form
   3,861.30/5,781.42 = 2,815.86/x
3. Step 3: Cross multiply
   3,861.30x = 5,781.42 × 2,815.86
4. Step 4: Simplify right side
   3,861.30x = 16,279,669.32
5. Step 5: Solve for x
   x = 16,279,669.32/3,861.30
6. Step 6: Final answer
   x = 4,216.11