Finding the Fourth Proportional to 85.65, 128.37 and 42.27

Step by Step Solution

1. Step 1: Write the proportion equation
   85.65 : 128.37 = 42.27 : x
2. Step 2: Convert to fraction form
   85.65/128.37 = 42.27/x
3. Step 3: Cross multiply
   85.65x = 128.37 × 42.27
4. Step 4: Simplify right side
   85.65x = 5,426.20
5. Step 5: Solve for x
   x = 5,426.20/85.65
6. Step 6: Final answer
   x = 63.35