Finding the Fourth Proportional to 105.25, 145.25 and 61.61

Step by Step Solution

1. Step 1: Write the proportion equation
   105.25 : 145.25 = 61.61 : x
2. Step 2: Convert to fraction form
   105.25/145.25 = 61.61/x
3. Step 3: Cross multiply
   105.25x = 145.25 × 61.61
4. Step 4: Simplify right side
   105.25x = 8,948.54
5. Step 5: Solve for x
   x = 8,948.54/105.25
6. Step 6: Final answer
   x = 85.02