Finding the Fourth Proportional to 72.78, 109.20 and 48.78

Step by Step Solution

1. Step 1: Write the proportion equation
   72.78 : 109.20 = 48.78 : x
2. Step 2: Convert to fraction form
   72.78/109.20 = 48.78/x
3. Step 3: Cross multiply
   72.78x = 109.20 × 48.78
4. Step 4: Simplify right side
   72.78x = 5,326.78
5. Step 5: Solve for x
   x = 5,326.78/72.78
6. Step 6: Final answer
   x = 73.19