Finding the Fourth Proportional to 105.51, 145.28 and 89.94

Step by Step Solution

1. Step 1: Write the proportion equation
   105.51 : 145.28 = 89.94 : x
2. Step 2: Convert to fraction form
   105.51/145.28 = 89.94/x
3. Step 3: Cross multiply
   105.51x = 145.28 × 89.94
4. Step 4: Simplify right side
   105.51x = 13,066.48
5. Step 5: Solve for x
   x = 13,066.48/105.51
6. Step 6: Final answer
   x = 123.84