Finding the Fourth Proportional to 139.58, 192.56 and 90.38

Step by Step Solution

1. Step 1: Write the proportion equation
   139.58 : 192.56 = 90.38 : x
2. Step 2: Convert to fraction form
   139.58/192.56 = 90.38/x
3. Step 3: Cross multiply
   139.58x = 192.56 × 90.38
4. Step 4: Simplify right side
   139.58x = 17,403.57
5. Step 5: Solve for x
   x = 17,403.57/139.58
6. Step 6: Final answer
   x = 124.69