Finding the Fourth Proportional to 103.67, 142.31 and 89.09

Step by Step Solution

1. Step 1: Write the proportion equation
   103.67 : 142.31 = 89.09 : x
2. Step 2: Convert to fraction form
   103.67/142.31 = 89.09/x
3. Step 3: Cross multiply
   103.67x = 142.31 × 89.09
4. Step 4: Simplify right side
   103.67x = 12,678.40
5. Step 5: Solve for x
   x = 12,678.40/103.67
6. Step 6: Final answer
   x = 122.30