Finding the Fourth Proportional to 105.10, 145.06 and 61.42

Step by Step Solution

1. Step 1: Write the proportion equation
   105.10 : 145.06 = 61.42 : x
2. Step 2: Convert to fraction form
   105.10/145.06 = 61.42/x
3. Step 3: Cross multiply
   105.10x = 145.06 × 61.42
4. Step 4: Simplify right side
   105.10x = 8,909.59
5. Step 5: Solve for x
   x = 8,909.59/105.10
6. Step 6: Final answer
   x = 84.77