Finding the Fourth Proportional to 103.55, 142.55 and 89.69

Step by Step Solution

1. Step 1: Write the proportion equation
   103.55 : 142.55 = 89.69 : x
2. Step 2: Convert to fraction form
   103.55/142.55 = 89.69/x
3. Step 3: Cross multiply
   103.55x = 142.55 × 89.69
4. Step 4: Simplify right side
   103.55x = 12,784.82
5. Step 5: Solve for x
   x = 12,784.82/103.55
6. Step 6: Final answer
   x = 123.47