Finding the Fourth Proportional to 139,010.60, 208,710.30 and 86,522.60

Step by Step Solution

1. Step 1: Write the proportion equation
   139,010.60 : 208,710.30 = 86,522.60 : x
2. Step 2: Convert to fraction form
   139,010.60/208,710.30 = 86,522.60/x
3. Step 3: Cross multiply
   139,010.60x = 208,710.30 × 86,522.60
4. Step 4: Simplify right side
   139,010.60x = 18,058,157,802.78
5. Step 5: Solve for x
   x = 18,058,157,802.78/139,010.60
6. Step 6: Final answer
   x = 129,904.90