Finding the Fourth Proportional to 139.74, 192.83 and 90.71

Step by Step Solution

1. Step 1: Write the proportion equation
   139.74 : 192.83 = 90.71 : x
2. Step 2: Convert to fraction form
   139.74/192.83 = 90.71/x
3. Step 3: Cross multiply
   139.74x = 192.83 × 90.71
4. Step 4: Simplify right side
   139.74x = 17,491.61
5. Step 5: Solve for x
   x = 17,491.61/139.74
6. Step 6: Final answer
   x = 125.17