Finding the Fourth Proportional to 139.41, 208.71 and 104.96

Step by Step Solution

1. Step 1: Write the proportion equation
   139.41 : 208.71 = 104.96 : x
2. Step 2: Convert to fraction form
   139.41/208.71 = 104.96/x
3. Step 3: Cross multiply
   139.41x = 208.71 × 104.96
4. Step 4: Simplify right side
   139.41x = 21,906.72
5. Step 5: Solve for x
   x = 21,906.72/139.41
6. Step 6: Final answer
   x = 157.14