Finding the Fourth Proportional to 78.82, 108.78 and 49.72

Step by Step Solution

1. Step 1: Write the proportion equation
   78.82 : 108.78 = 49.72 : x
2. Step 2: Convert to fraction form
   78.82/108.78 = 49.72/x
3. Step 3: Cross multiply
   78.82x = 108.78 × 49.72
4. Step 4: Simplify right side
   78.82x = 5,408.54
5. Step 5: Solve for x
   x = 5,408.54/78.82
6. Step 6: Final answer
   x = 68.62