Finding the Fourth Proportional to 9,139.17, 12,612.05 and 5,160.54

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.17 : 12,612.05 = 5,160.54 : x
2. Step 2: Convert to fraction form
   9,139.17/12,612.05 = 5,160.54/x
3. Step 3: Cross multiply
   9,139.17x = 12,612.05 × 5,160.54
4. Step 4: Simplify right side
   9,139.17x = 65,084,922.94
5. Step 5: Solve for x
   x = 65,084,922.94/9,139.17
6. Step 6: Final answer
   x = 7,121.54