Finding the Fourth Proportional to 105.50, 158.18 and 71.28

Step by Step Solution

1. Step 1: Write the proportion equation
   105.50 : 158.18 = 71.28 : x
2. Step 2: Convert to fraction form
   105.50/158.18 = 71.28/x
3. Step 3: Cross multiply
   105.50x = 158.18 × 71.28
4. Step 4: Simplify right side
   105.50x = 11,274.71
5. Step 5: Solve for x
   x = 11,274.71/105.50
6. Step 6: Final answer
   x = 106.87