Finding the Fourth Proportional to 139.28, 192.52 and 100.80

Step by Step Solution

1. Step 1: Write the proportion equation
   139.28 : 192.52 = 100.80 : x
2. Step 2: Convert to fraction form
   139.28/192.52 = 100.80/x
3. Step 3: Cross multiply
   139.28x = 192.52 × 100.80
4. Step 4: Simplify right side
   139.28x = 19,406.02
5. Step 5: Solve for x
   x = 19,406.02/139.28
6. Step 6: Final answer
   x = 139.33