Finding the Fourth Proportional to 104.78, 144.56 and 71.96

Step by Step Solution

1. Step 1: Write the proportion equation
   104.78 : 144.56 = 71.96 : x
2. Step 2: Convert to fraction form
   104.78/144.56 = 71.96/x
3. Step 3: Cross multiply
   104.78x = 144.56 × 71.96
4. Step 4: Simplify right side
   104.78x = 10,402.54
5. Step 5: Solve for x
   x = 10,402.54/104.78
6. Step 6: Final answer
   x = 99.28