Finding the Fourth Proportional to 21,791.89, 30,086.81 and 13,413.25

Step by Step Solution

1. Step 1: Write the proportion equation
   21,791.89 : 30,086.81 = 13,413.25 : x
2. Step 2: Convert to fraction form
   21,791.89/30,086.81 = 13,413.25/x
3. Step 3: Cross multiply
   21,791.89x = 30,086.81 × 13,413.25
4. Step 4: Simplify right side
   21,791.89x = 403,561,904.23
5. Step 5: Solve for x
   x = 403,561,904.23/21,791.89
6. Step 6: Final answer
   x = 18,518.90