Finding the Fourth Proportional to 71.70, 107.46 and 42.72

Step by Step Solution

1. Step 1: Write the proportion equation
   71.70 : 107.46 = 42.72 : x
2. Step 2: Convert to fraction form
   71.70/107.46 = 42.72/x
3. Step 3: Cross multiply
   71.70x = 107.46 × 42.72
4. Step 4: Simplify right side
   71.70x = 4,590.69
5. Step 5: Solve for x
   x = 4,590.69/71.70
6. Step 6: Final answer
   x = 64.03