Finding the Fourth Proportional to 139.29, 192.10 and 89.50

Step by Step Solution

1. Step 1: Write the proportion equation
   139.29 : 192.10 = 89.50 : x
2. Step 2: Convert to fraction form
   139.29/192.10 = 89.50/x
3. Step 3: Cross multiply
   139.29x = 192.10 × 89.50
4. Step 4: Simplify right side
   139.29x = 17,192.83
5. Step 5: Solve for x
   x = 17,192.83/139.29
6. Step 6: Final answer
   x = 123.44