Finding the Fourth Proportional to 139.78, 192.90 and 104.82

Step by Step Solution

1. Step 1: Write the proportion equation
   139.78 : 192.90 = 104.82 : x
2. Step 2: Convert to fraction form
   139.78/192.90 = 104.82/x
3. Step 3: Cross multiply
   139.78x = 192.90 × 104.82
4. Step 4: Simplify right side
   139.78x = 20,219.78
5. Step 5: Solve for x
   x = 20,219.78/139.78
6. Step 6: Final answer
   x = 144.65