Finding the Fourth Proportional to 105.23, 145.23 and 89.69

Step by Step Solution

1. Step 1: Write the proportion equation
   105.23 : 145.23 = 89.69 : x
2. Step 2: Convert to fraction form
   105.23/145.23 = 89.69/x
3. Step 3: Cross multiply
   105.23x = 145.23 × 89.69
4. Step 4: Simplify right side
   105.23x = 13,024.62
5. Step 5: Solve for x
   x = 13,024.62/105.23
6. Step 6: Final answer
   x = 123.77