Finding the Fourth Proportional to 111.31, 166.83 and 57.18

Step by Step Solution

1. Step 1: Write the proportion equation
   111.31 : 166.83 = 57.18 : x
2. Step 2: Convert to fraction form
   111.31/166.83 = 57.18/x
3. Step 3: Cross multiply
   111.31x = 166.83 × 57.18
4. Step 4: Simplify right side
   111.31x = 9,539.34
5. Step 5: Solve for x
   x = 9,539.34/111.31
6. Step 6: Final answer
   x = 85.70