Finding the Fourth Proportional to 21,288.42, 31,956.12 and 12,413.25

Step by Step Solution

1. Step 1: Write the proportion equation
   21,288.42 : 31,956.12 = 12,413.25 : x
2. Step 2: Convert to fraction form
   21,288.42/31,956.12 = 12,413.25/x
3. Step 3: Cross multiply
   21,288.42x = 31,956.12 × 12,413.25
4. Step 4: Simplify right side
   21,288.42x = 396,679,306.59
5. Step 5: Solve for x
   x = 396,679,306.59/21,288.42
6. Step 6: Final answer
   x = 18,633.57