Finding the Fourth Proportional to 139.61, 192.62 and 90.47

Step by Step Solution

1. Step 1: Write the proportion equation
   139.61 : 192.62 = 90.47 : x
2. Step 2: Convert to fraction form
   139.61/192.62 = 90.47/x
3. Step 3: Cross multiply
   139.61x = 192.62 × 90.47
4. Step 4: Simplify right side
   139.61x = 17,424.92
5. Step 5: Solve for x
   x = 17,424.92/139.61
6. Step 6: Final answer
   x = 124.82