Finding the Fourth Proportional to 105.57, 158.31 and 57.42

Step by Step Solution

1. Step 1: Write the proportion equation
   105.57 : 158.31 = 57.42 : x
2. Step 2: Convert to fraction form
   105.57/158.31 = 57.42/x
3. Step 3: Cross multiply
   105.57x = 158.31 × 57.42
4. Step 4: Simplify right side
   105.57x = 9,090.16
5. Step 5: Solve for x
   x = 9,090.16/105.57
6. Step 6: Final answer
   x = 86.11