Finding the Fourth Proportional to 111.12, 166.64 and 42.61

Step by Step Solution

1. Step 1: Write the proportion equation
   111.12 : 166.64 = 42.61 : x
2. Step 2: Convert to fraction form
   111.12/166.64 = 42.61/x
3. Step 3: Cross multiply
   111.12x = 166.64 × 42.61
4. Step 4: Simplify right side
   111.12x = 7,100.53
5. Step 5: Solve for x
   x = 7,100.53/111.12
6. Step 6: Final answer
   x = 63.90