Finding the Fourth Proportional to 103.50, 142.88 and 90.41

Step by Step Solution

1. Step 1: Write the proportion equation
   103.50 : 142.88 = 90.41 : x
2. Step 2: Convert to fraction form
   103.50/142.88 = 90.41/x
3. Step 3: Cross multiply
   103.50x = 142.88 × 90.41
4. Step 4: Simplify right side
   103.50x = 12,916.61
5. Step 5: Solve for x
   x = 12,916.61/103.50
6. Step 6: Final answer
   x = 124.80