Finding the Fourth Proportional to 3,889.66, 5,324.78 and 3,861.86

Step by Step Solution

1. Step 1: Write the proportion equation
   3,889.66 : 5,324.78 = 3,861.86 : x
2. Step 2: Convert to fraction form
   3,889.66/5,324.78 = 3,861.86/x
3. Step 3: Cross multiply
   3,889.66x = 5,324.78 × 3,861.86
4. Step 4: Simplify right side
   3,889.66x = 20,563,548.89
5. Step 5: Solve for x
   x = 20,563,548.89/3,889.66
6. Step 6: Final answer
   x = 5,286.72