Finding the Fourth Proportional to 143.98, 215.76 and 71.89

Step by Step Solution

1. Step 1: Write the proportion equation
   143.98 : 215.76 = 71.89 : x
2. Step 2: Convert to fraction form
   143.98/215.76 = 71.89/x
3. Step 3: Cross multiply
   143.98x = 215.76 × 71.89
4. Step 4: Simplify right side
   143.98x = 15,510.72
5. Step 5: Solve for x
   x = 15,510.72/143.98
6. Step 6: Final answer
   x = 107.73