Finding the Fourth Proportional to 9,861.31, 13,608.71 and 5,385.11

Step by Step Solution

1. Step 1: Write the proportion equation
   9,861.31 : 13,608.71 = 5,385.11 : x
2. Step 2: Convert to fraction form
   9,861.31/13,608.71 = 5,385.11/x
3. Step 3: Cross multiply
   9,861.31x = 13,608.71 × 5,385.11
4. Step 4: Simplify right side
   9,861.31x = 73,284,413.77
5. Step 5: Solve for x
   x = 73,284,413.77/9,861.31
6. Step 6: Final answer
   x = 7,431.51