Finding the Fourth Proportional to 111.98, 167.70 and 71.42

Step by Step Solution

1. Step 1: Write the proportion equation
   111.98 : 167.70 = 71.42 : x
2. Step 2: Convert to fraction form
   111.98/167.70 = 71.42/x
3. Step 3: Cross multiply
   111.98x = 167.70 × 71.42
4. Step 4: Simplify right side
   111.98x = 11,976.56
5. Step 5: Solve for x
   x = 11,976.56/111.98
6. Step 6: Final answer
   x = 106.95