Finding the Fourth Proportional to 78.78, 108.78 and 49.68

Step by Step Solution

1. Step 1: Write the proportion equation
   78.78 : 108.78 = 49.68 : x
2. Step 2: Convert to fraction form
   78.78/108.78 = 49.68/x
3. Step 3: Cross multiply
   78.78x = 108.78 × 49.68
4. Step 4: Simplify right side
   78.78x = 5,404.19
5. Step 5: Solve for x
   x = 5,404.19/78.78
6. Step 6: Final answer
   x = 68.60