Finding the Fourth Proportional to 139.50, 209.13 and 100.96

Step by Step Solution

1. Step 1: Write the proportion equation
   139.50 : 209.13 = 100.96 : x
2. Step 2: Convert to fraction form
   139.50/209.13 = 100.96/x
3. Step 3: Cross multiply
   139.50x = 209.13 × 100.96
4. Step 4: Simplify right side
   139.50x = 21,113.76
5. Step 5: Solve for x
   x = 21,113.76/139.50
6. Step 6: Final answer
   x = 151.35