Finding the Fourth Proportional to 105.30, 145.26 and 89.10

Step by Step Solution

1. Step 1: Write the proportion equation
   105.30 : 145.26 = 89.10 : x
2. Step 2: Convert to fraction form
   105.30/145.26 = 89.10/x
3. Step 3: Cross multiply
   105.30x = 145.26 × 89.10
4. Step 4: Simplify right side
   105.30x = 12,942.67
5. Step 5: Solve for x
   x = 12,942.67/105.30
6. Step 6: Final answer
   x = 122.91