Finding the Fourth Proportional to 111.77, 167.59 and 81.29

Step by Step Solution

1. Step 1: Write the proportion equation
   111.77 : 167.59 = 81.29 : x
2. Step 2: Convert to fraction form
   111.77/167.59 = 81.29/x
3. Step 3: Cross multiply
   111.77x = 167.59 × 81.29
4. Step 4: Simplify right side
   111.77x = 13,622.35
5. Step 5: Solve for x
   x = 13,622.35/111.77
6. Step 6: Final answer
   x = 121.88