Finding the Fourth Proportional to 12,978.26, 17,910.36 and 7,942.39

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.26 : 17,910.36 = 7,942.39 : x
2. Step 2: Convert to fraction form
   12,978.26/17,910.36 = 7,942.39/x
3. Step 3: Cross multiply
   12,978.26x = 17,910.36 × 7,942.39
4. Step 4: Simplify right side
   12,978.26x = 142,251,064.16
5. Step 5: Solve for x
   x = 142,251,064.16/12,978.26
6. Step 6: Final answer
   x = 10,960.72