Finding the Fourth Proportional to 111.42, 167.70 and 81.18

Step by Step Solution

1. Step 1: Write the proportion equation
   111.42 : 167.70 = 81.18 : x
2. Step 2: Convert to fraction form
   111.42/167.70 = 81.18/x
3. Step 3: Cross multiply
   111.42x = 167.70 × 81.18
4. Step 4: Simplify right side
   111.42x = 13,613.89
5. Step 5: Solve for x
   x = 13,613.89/111.42
6. Step 6: Final answer
   x = 122.19