Finding the Fourth Proportional to 103.89, 143.42 and 71.31

Step by Step Solution

1. Step 1: Write the proportion equation
   103.89 : 143.42 = 71.31 : x
2. Step 2: Convert to fraction form
   103.89/143.42 = 71.31/x
3. Step 3: Cross multiply
   103.89x = 143.42 × 71.31
4. Step 4: Simplify right side
   103.89x = 10,226.92
5. Step 5: Solve for x
   x = 10,226.92/103.89
6. Step 6: Final answer
   x = 98.44