Finding the Fourth Proportional to 100.92, 139.32 and 100.38

Step by Step Solution

1. Step 1: Write the proportion equation
   100.92 : 139.32 = 100.38 : x
2. Step 2: Convert to fraction form
   100.92/139.32 = 100.38/x
3. Step 3: Cross multiply
   100.92x = 139.32 × 100.38
4. Step 4: Simplify right side
   100.92x = 13,984.94
5. Step 5: Solve for x
   x = 13,984.94/100.92
6. Step 6: Final answer
   x = 138.57