Finding the Fourth Proportional to 9,162.57, 12,640.89 and 5,385.90

Step by Step Solution

1. Step 1: Write the proportion equation
   9,162.57 : 12,640.89 = 5,385.90 : x
2. Step 2: Convert to fraction form
   9,162.57/12,640.89 = 5,385.90/x
3. Step 3: Cross multiply
   9,162.57x = 12,640.89 × 5,385.90
4. Step 4: Simplify right side
   9,162.57x = 68,082,569.45
5. Step 5: Solve for x
   x = 68,082,569.45/9,162.57
6. Step 6: Final answer
   x = 7,430.51