Finding the Fourth Proportional to 105.18, 145 and 83.10

Step by Step Solution

1. Step 1: Write the proportion equation
   105.18 : 145 = 83.10 : x
2. Step 2: Convert to fraction form
   105.18/145 = 83.10/x
3. Step 3: Cross multiply
   105.18x = 145 × 83.10
4. Step 4: Simplify right side
   105.18x = 12,049.50
5. Step 5: Solve for x
   x = 12,049.50/105.18
6. Step 6: Final answer
   x = 114.56