Finding the Fourth Proportional to 139.45, 192.37 and 90.38

Step by Step Solution

1. Step 1: Write the proportion equation
   139.45 : 192.37 = 90.38 : x
2. Step 2: Convert to fraction form
   139.45/192.37 = 90.38/x
3. Step 3: Cross multiply
   139.45x = 192.37 × 90.38
4. Step 4: Simplify right side
   139.45x = 17,386.17
5. Step 5: Solve for x
   x = 17,386.17/139.45
6. Step 6: Final answer
   x = 124.67