Finding the Fourth Proportional to 72.78, 108.75 and 71.49

Step by Step Solution

1. Step 1: Write the proportion equation
   72.78 : 108.75 = 71.49 : x
2. Step 2: Convert to fraction form
   72.78/108.75 = 71.49/x
3. Step 3: Cross multiply
   72.78x = 108.75 × 71.49
4. Step 4: Simplify right side
   72.78x = 7,774.54
5. Step 5: Solve for x
   x = 7,774.54/72.78
6. Step 6: Final answer
   x = 106.82