Finding the Fourth Proportional to 139.37, 209.31 and 88.10

Step by Step Solution

1. Step 1: Write the proportion equation
   139.37 : 209.31 = 88.10 : x
2. Step 2: Convert to fraction form
   139.37/209.31 = 88.10/x
3. Step 3: Cross multiply
   139.37x = 209.31 × 88.10
4. Step 4: Simplify right side
   139.37x = 18,439.16
5. Step 5: Solve for x
   x = 18,439.16/139.37
6. Step 6: Final answer
   x = 132.31