Finding the Fourth Proportional to 139.71, 209.17 and 105.37

Step by Step Solution

1. Step 1: Write the proportion equation
   139.71 : 209.17 = 105.37 : x
2. Step 2: Convert to fraction form
   139.71/209.17 = 105.37/x
3. Step 3: Cross multiply
   139.71x = 209.17 × 105.37
4. Step 4: Simplify right side
   139.71x = 22,040.15
5. Step 5: Solve for x
   x = 22,040.15/139.71
6. Step 6: Final answer
   x = 157.75