Finding the Fourth Proportional to 105.21, 145.35 and 89.83

Step by Step Solution

1. Step 1: Write the proportion equation
   105.21 : 145.35 = 89.83 : x
2. Step 2: Convert to fraction form
   105.21/145.35 = 89.83/x
3. Step 3: Cross multiply
   105.21x = 145.35 × 89.83
4. Step 4: Simplify right side
   105.21x = 13,056.79
5. Step 5: Solve for x
   x = 13,056.79/105.21
6. Step 6: Final answer
   x = 124.10