Finding the Fourth Proportional to 105.07, 144.90 and 89.57

Step by Step Solution

1. Step 1: Write the proportion equation
   105.07 : 144.90 = 89.57 : x
2. Step 2: Convert to fraction form
   105.07/144.90 = 89.57/x
3. Step 3: Cross multiply
   105.07x = 144.90 × 89.57
4. Step 4: Simplify right side
   105.07x = 12,978.69
5. Step 5: Solve for x
   x = 12,978.69/105.07
6. Step 6: Final answer
   x = 123.53