Finding the Fourth Proportional to 139.47, 209.50 and 103.61

Step by Step Solution

1. Step 1: Write the proportion equation
   139.47 : 209.50 = 103.61 : x
2. Step 2: Convert to fraction form
   139.47/209.50 = 103.61/x
3. Step 3: Cross multiply
   139.47x = 209.50 × 103.61
4. Step 4: Simplify right side
   139.47x = 21,706.30
5. Step 5: Solve for x
   x = 21,706.30/139.47
6. Step 6: Final answer
   x = 155.63