Finding the Fourth Proportional to 71.69, 107.40 and 42.71

Step by Step Solution

1. Step 1: Write the proportion equation
   71.69 : 107.40 = 42.71 : x
2. Step 2: Convert to fraction form
   71.69/107.40 = 42.71/x
3. Step 3: Cross multiply
   71.69x = 107.40 × 42.71
4. Step 4: Simplify right side
   71.69x = 4,587.16
5. Step 5: Solve for x
   x = 4,587.16/71.69
6. Step 6: Final answer
   x = 63.99