Finding the Fourth Proportional to 78.96, 108.96 and 54.39

Step by Step Solution

1. Step 1: Write the proportion equation
   78.96 : 108.96 = 54.39 : x
2. Step 2: Convert to fraction form
   78.96/108.96 = 54.39/x
3. Step 3: Cross multiply
   78.96x = 108.96 × 54.39
4. Step 4: Simplify right side
   78.96x = 5,926.33
5. Step 5: Solve for x
   x = 5,926.33/78.96
6. Step 6: Final answer
   x = 75.05