Finding the Fourth Proportional to 105.98, 158.72 and 54.49

Step by Step Solution

1. Step 1: Write the proportion equation
   105.98 : 158.72 = 54.49 : x
2. Step 2: Convert to fraction form
   105.98/158.72 = 54.49/x
3. Step 3: Cross multiply
   105.98x = 158.72 × 54.49
4. Step 4: Simplify right side
   105.98x = 8,648.38
5. Step 5: Solve for x
   x = 8,648.38/105.98
6. Step 6: Final answer
   x = 81.61