Finding the Fourth Proportional to 139.58, 209.15 and 123.29

Step by Step Solution

1. Step 1: Write the proportion equation
   139.58 : 209.15 = 123.29 : x
2. Step 2: Convert to fraction form
   139.58/209.15 = 123.29/x
3. Step 3: Cross multiply
   139.58x = 209.15 × 123.29
4. Step 4: Simplify right side
   139.58x = 25,786.10
5. Step 5: Solve for x
   x = 25,786.10/139.58
6. Step 6: Final answer
   x = 184.74