Finding the Fourth Proportional to 139.28, 192.24 and 104.72

Step by Step Solution

1. Step 1: Write the proportion equation
   139.28 : 192.24 = 104.72 : x
2. Step 2: Convert to fraction form
   139.28/192.24 = 104.72/x
3. Step 3: Cross multiply
   139.28x = 192.24 × 104.72
4. Step 4: Simplify right side
   139.28x = 20,131.37
5. Step 5: Solve for x
   x = 20,131.37/139.28
6. Step 6: Final answer
   x = 144.54