Finding the Fourth Proportional to 72.71, 109.10 and 71.18

Step by Step Solution

1. Step 1: Write the proportion equation
   72.71 : 109.10 = 71.18 : x
2. Step 2: Convert to fraction form
   72.71/109.10 = 71.18/x
3. Step 3: Cross multiply
   72.71x = 109.10 × 71.18
4. Step 4: Simplify right side
   72.71x = 7,765.38
5. Step 5: Solve for x
   x = 7,765.38/72.71
6. Step 6: Final answer
   x = 106.79