Finding the Fourth Proportional to 413.82, 620.82 and 139.86

Step by Step Solution

1. Step 1: Write the proportion equation
   413.82 : 620.82 = 139.86 : x
2. Step 2: Convert to fraction form
   413.82/620.82 = 139.86/x
3. Step 3: Cross multiply
   413.82x = 620.82 × 139.86
4. Step 4: Simplify right side
   413.82x = 86,827.89
5. Step 5: Solve for x
   x = 86,827.89/413.82
6. Step 6: Final answer
   x = 209.82