Finding the Fourth Proportional to 85.82, 128.76 and 42.48

Step by Step Solution

1. Step 1: Write the proportion equation
   85.82 : 128.76 = 42.48 : x
2. Step 2: Convert to fraction form
   85.82/128.76 = 42.48/x
3. Step 3: Cross multiply
   85.82x = 128.76 × 42.48
4. Step 4: Simplify right side
   85.82x = 5,469.72
5. Step 5: Solve for x
   x = 5,469.72/85.82
6. Step 6: Final answer
   x = 63.73