Finding the Fourth Proportional to 78.69, 108.55 and 49.57

Step by Step Solution

1. Step 1: Write the proportion equation
   78.69 : 108.55 = 49.57 : x
2. Step 2: Convert to fraction form
   78.69/108.55 = 49.57/x
3. Step 3: Cross multiply
   78.69x = 108.55 × 49.57
4. Step 4: Simplify right side
   78.69x = 5,380.82
5. Step 5: Solve for x
   x = 5,380.82/78.69
6. Step 6: Final answer
   x = 68.38