Finding the Fourth Proportional to 139.52, 192.50 and 90.42

Step by Step Solution

1. Step 1: Write the proportion equation
   139.52 : 192.50 = 90.42 : x
2. Step 2: Convert to fraction form
   139.52/192.50 = 90.42/x
3. Step 3: Cross multiply
   139.52x = 192.50 × 90.42
4. Step 4: Simplify right side
   139.52x = 17,405.85
5. Step 5: Solve for x
   x = 17,405.85/139.52
6. Step 6: Final answer
   x = 124.76