Finding the Fourth Proportional to 139.89, 209.64 and 109.31

Step by Step Solution

1. Step 1: Write the proportion equation
   139.89 : 209.64 = 109.31 : x
2. Step 2: Convert to fraction form
   139.89/209.64 = 109.31/x
3. Step 3: Cross multiply
   139.89x = 209.64 × 109.31
4. Step 4: Simplify right side
   139.89x = 22,916.27
5. Step 5: Solve for x
   x = 22,916.27/139.89
6. Step 6: Final answer
   x = 163.82