Finding the Fourth Proportional to 139.56, 192.53 and 90.42

Step by Step Solution

1. Step 1: Write the proportion equation
   139.56 : 192.53 = 90.42 : x
2. Step 2: Convert to fraction form
   139.56/192.53 = 90.42/x
3. Step 3: Cross multiply
   139.56x = 192.53 × 90.42
4. Step 4: Simplify right side
   139.56x = 17,408.56
5. Step 5: Solve for x
   x = 17,408.56/139.56
6. Step 6: Final answer
   x = 124.74