Finding the Fourth Proportional to 103.42, 142.56 and 89.56

Step by Step Solution

1. Step 1: Write the proportion equation
   103.42 : 142.56 = 89.56 : x
2. Step 2: Convert to fraction form
   103.42/142.56 = 89.56/x
3. Step 3: Cross multiply
   103.42x = 142.56 × 89.56
4. Step 4: Simplify right side
   103.42x = 12,767.67
5. Step 5: Solve for x
   x = 12,767.67/103.42
6. Step 6: Final answer
   x = 123.45