Finding the Fourth Proportional to 103.48, 142.82 and 89.71

Step by Step Solution

1. Step 1: Write the proportion equation
   103.48 : 142.82 = 89.71 : x
2. Step 2: Convert to fraction form
   103.48/142.82 = 89.71/x
3. Step 3: Cross multiply
   103.48x = 142.82 × 89.71
4. Step 4: Simplify right side
   103.48x = 12,811.93
5. Step 5: Solve for x
   x = 12,811.93/103.48
6. Step 6: Final answer
   x = 123.81