Finding the Fourth Proportional to 21,978.18, 30,326.13 and 12,413.70

Step by Step Solution

1. Step 1: Write the proportion equation
   21,978.18 : 30,326.13 = 12,413.70 : x
2. Step 2: Convert to fraction form
   21,978.18/30,326.13 = 12,413.70/x
3. Step 3: Cross multiply
   21,978.18x = 30,326.13 × 12,413.70
4. Step 4: Simplify right side
   21,978.18x = 376,459,479.98
5. Step 5: Solve for x
   x = 376,459,479.98/21,978.18
6. Step 6: Final answer
   x = 17,128.78