Finding the Fourth Proportional to 12,370.16, 17,078.73 and 8,128.78

Step by Step Solution

1. Step 1: Write the proportion equation
   12,370.16 : 17,078.73 = 8,128.78 : x
2. Step 2: Convert to fraction form
   12,370.16/17,078.73 = 8,128.78/x
3. Step 3: Cross multiply
   12,370.16x = 17,078.73 × 8,128.78
4. Step 4: Simplify right side
   12,370.16x = 138,829,238.85
5. Step 5: Solve for x
   x = 138,829,238.85/12,370.16
6. Step 6: Final answer
   x = 11,222.91