Finding the Fourth Proportional to 139.22, 208.89 and 100.61

Step by Step Solution

1. Step 1: Write the proportion equation
   139.22 : 208.89 = 100.61 : x
2. Step 2: Convert to fraction form
   139.22/208.89 = 100.61/x
3. Step 3: Cross multiply
   139.22x = 208.89 × 100.61
4. Step 4: Simplify right side
   139.22x = 21,016.42
5. Step 5: Solve for x
   x = 21,016.42/139.22
6. Step 6: Final answer
   x = 150.96