Finding the Fourth Proportional to 8,128.62, 12,139.55 and 7,009.17

Step by Step Solution

1. Step 1: Write the proportion equation
   8,128.62 : 12,139.55 = 7,009.17 : x
2. Step 2: Convert to fraction form
   8,128.62/12,139.55 = 7,009.17/x
3. Step 3: Cross multiply
   8,128.62x = 12,139.55 × 7,009.17
4. Step 4: Simplify right side
   8,128.62x = 85,088,134.63
5. Step 5: Solve for x
   x = 85,088,134.63/8,128.62
6. Step 6: Final answer
   x = 10,467.72