Finding the Fourth Proportional to 85.83, 128.69 and 42.49

Step by Step Solution

1. Step 1: Write the proportion equation
   85.83 : 128.69 = 42.49 : x
2. Step 2: Convert to fraction form
   85.83/128.69 = 42.49/x
3. Step 3: Cross multiply
   85.83x = 128.69 × 42.49
4. Step 4: Simplify right side
   85.83x = 5,468.04
5. Step 5: Solve for x
   x = 5,468.04/85.83
6. Step 6: Final answer
   x = 63.71