Finding the Fourth Proportional to 10,128.78, 15,143.25 and 8,586.04

Step by Step Solution

1. Step 1: Write the proportion equation
   10,128.78 : 15,143.25 = 8,586.04 : x
2. Step 2: Convert to fraction form
   10,128.78/15,143.25 = 8,586.04/x
3. Step 3: Cross multiply
   10,128.78x = 15,143.25 × 8,586.04
4. Step 4: Simplify right side
   10,128.78x = 130,020,550.23
5. Step 5: Solve for x
   x = 130,020,550.23/10,128.78
6. Step 6: Final answer
   x = 12,836.74