Finding the Fourth Proportional to 85.88, 128.85 and 42.54

Step by Step Solution

1. Step 1: Write the proportion equation
   85.88 : 128.85 = 42.54 : x
2. Step 2: Convert to fraction form
   85.88/128.85 = 42.54/x
3. Step 3: Cross multiply
   85.88x = 128.85 × 42.54
4. Step 4: Simplify right side
   85.88x = 5,481.28
5. Step 5: Solve for x
   x = 5,481.28/85.88
6. Step 6: Final answer
   x = 63.83