Finding the Fourth Proportional to 111.91, 167.79 and 71.29

Step by Step Solution

1. Step 1: Write the proportion equation
   111.91 : 167.79 = 71.29 : x
2. Step 2: Convert to fraction form
   111.91/167.79 = 71.29/x
3. Step 3: Cross multiply
   111.91x = 167.79 × 71.29
4. Step 4: Simplify right side
   111.91x = 11,961.75
5. Step 5: Solve for x
   x = 11,961.75/111.91
6. Step 6: Final answer
   x = 106.89