Finding the Fourth Proportional to 139.48, 192.56 and 90.48

Step by Step Solution

1. Step 1: Write the proportion equation
   139.48 : 192.56 = 90.48 : x
2. Step 2: Convert to fraction form
   139.48/192.56 = 90.48/x
3. Step 3: Cross multiply
   139.48x = 192.56 × 90.48
4. Step 4: Simplify right side
   139.48x = 17,422.83
5. Step 5: Solve for x
   x = 17,422.83/139.48
6. Step 6: Final answer
   x = 124.91