Finding the Fourth Proportional to 139.37, 192.25 and 89.57

Step by Step Solution

1. Step 1: Write the proportion equation
   139.37 : 192.25 = 89.57 : x
2. Step 2: Convert to fraction form
   139.37/192.25 = 89.57/x
3. Step 3: Cross multiply
   139.37x = 192.25 × 89.57
4. Step 4: Simplify right side
   139.37x = 17,219.83
5. Step 5: Solve for x
   x = 17,219.83/139.37
6. Step 6: Final answer
   x = 123.55