Finding the Fourth Proportional to 103.49, 142.69 and 86.96

Step by Step Solution

1. Step 1: Write the proportion equation
   103.49 : 142.69 = 86.96 : x
2. Step 2: Convert to fraction form
   103.49/142.69 = 86.96/x
3. Step 3: Cross multiply
   103.49x = 142.69 × 86.96
4. Step 4: Simplify right side
   103.49x = 12,407.17
5. Step 5: Solve for x
   x = 12,407.17/103.49
6. Step 6: Final answer
   x = 119.89