Finding the Fourth Proportional to 85.95, 128.94 and 42.64

Step by Step Solution

1. Step 1: Write the proportion equation
   85.95 : 128.94 = 42.64 : x
2. Step 2: Convert to fraction form
   85.95/128.94 = 42.64/x
3. Step 3: Cross multiply
   85.95x = 128.94 × 42.64
4. Step 4: Simplify right side
   85.95x = 5,498.48
5. Step 5: Solve for x
   x = 5,498.48/85.95
6. Step 6: Final answer
   x = 63.97