Finding the Fourth Proportional to 139,701.83, 209,603.43 and 86,331.60

Step by Step Solution

1. Step 1: Write the proportion equation
   139,701.83 : 209,603.43 = 86,331.60 : x
2. Step 2: Convert to fraction form
   139,701.83/209,603.43 = 86,331.60/x
3. Step 3: Cross multiply
   139,701.83x = 209,603.43 × 86,331.60
4. Step 4: Simplify right side
   139,701.83x = 18,095,399,477.39
5. Step 5: Solve for x
   x = 18,095,399,477.39/139,701.83
6. Step 6: Final answer
   x = 129,528.73