Finding the Fourth Proportional to 85.41, 128.17 and 42.69

Step by Step Solution

1. Step 1: Write the proportion equation
   85.41 : 128.17 = 42.69 : x
2. Step 2: Convert to fraction form
   85.41/128.17 = 42.69/x
3. Step 3: Cross multiply
   85.41x = 128.17 × 42.69
4. Step 4: Simplify right side
   85.41x = 5,471.31
5. Step 5: Solve for x
   x = 5,471.31/85.41
6. Step 6: Final answer
   x = 64.06