Finding the Fourth Proportional to 105.69, 145.49 and 91.89

Step by Step Solution

1. Step 1: Write the proportion equation
   105.69 : 145.49 = 91.89 : x
2. Step 2: Convert to fraction form
   105.69/145.49 = 91.89/x
3. Step 3: Cross multiply
   105.69x = 145.49 × 91.89
4. Step 4: Simplify right side
   105.69x = 13,368.62
5. Step 5: Solve for x
   x = 13,368.62/105.69
6. Step 6: Final answer
   x = 126.49