Finding the Fourth Proportional to 105.34, 158.15 and 66.71

Step by Step Solution

1. Step 1: Write the proportion equation
   105.34 : 158.15 = 66.71 : x
2. Step 2: Convert to fraction form
   105.34/158.15 = 66.71/x
3. Step 3: Cross multiply
   105.34x = 158.15 × 66.71
4. Step 4: Simplify right side
   105.34x = 10,550.19
5. Step 5: Solve for x
   x = 10,550.19/105.34
6. Step 6: Final answer
   x = 100.15