Finding the Fourth Proportional to 12,128.16, 18,181.60 and 10,065.28

Step by Step Solution

1. Step 1: Write the proportion equation
   12,128.16 : 18,181.60 = 10,065.28 : x
2. Step 2: Convert to fraction form
   12,128.16/18,181.60 = 10,065.28/x
3. Step 3: Cross multiply
   12,128.16x = 18,181.60 × 10,065.28
4. Step 4: Simplify right side
   12,128.16x = 183,002,894.85
5. Step 5: Solve for x
   x = 183,002,894.85/12,128.16
6. Step 6: Final answer
   x = 15,089.09