Finding the Fourth Proportional to 12,794.12, 17,655.78 and 7,128.80

Step by Step Solution

1. Step 1: Write the proportion equation
   12,794.12 : 17,655.78 = 7,128.80 : x
2. Step 2: Convert to fraction form
   12,794.12/17,655.78 = 7,128.80/x
3. Step 3: Cross multiply
   12,794.12x = 17,655.78 × 7,128.80
4. Step 4: Simplify right side
   12,794.12x = 125,864,524.46
5. Step 5: Solve for x
   x = 125,864,524.46/12,794.12
6. Step 6: Final answer
   x = 9,837.69