Finding the Fourth Proportional to 28,413.28, 42,632.78 and 12,407.78

Step by Step Solution

1. Step 1: Write the proportion equation
   28,413.28 : 42,632.78 = 12,407.78 : x
2. Step 2: Convert to fraction form
   28,413.28/42,632.78 = 12,407.78/x
3. Step 3: Cross multiply
   28,413.28x = 42,632.78 × 12,407.78
4. Step 4: Simplify right side
   28,413.28x = 528,978,269.37
5. Step 5: Solve for x
   x = 528,978,269.37/28,413.28
6. Step 6: Final answer
   x = 18,617.29