Finding the Fourth Proportional to 105.78, 145.82 and 82.18

Step by Step Solution

1. Step 1: Write the proportion equation
   105.78 : 145.82 = 82.18 : x
2. Step 2: Convert to fraction form
   105.78/145.82 = 82.18/x
3. Step 3: Cross multiply
   105.78x = 145.82 × 82.18
4. Step 4: Simplify right side
   105.78x = 11,983.49
5. Step 5: Solve for x
   x = 11,983.49/105.78
6. Step 6: Final answer
   x = 113.29