Finding the Fourth Proportional to 105.54, 145.83 and 90.18

Step by Step Solution

1. Step 1: Write the proportion equation
   105.54 : 145.83 = 90.18 : x
2. Step 2: Convert to fraction form
   105.54/145.83 = 90.18/x
3. Step 3: Cross multiply
   105.54x = 145.83 × 90.18
4. Step 4: Simplify right side
   105.54x = 13,150.95
5. Step 5: Solve for x
   x = 13,150.95/105.54
6. Step 6: Final answer
   x = 124.61