Finding the Fourth Proportional to 71.72, 107.48 and 42.86

Step by Step Solution

1. Step 1: Write the proportion equation
   71.72 : 107.48 = 42.86 : x
2. Step 2: Convert to fraction form
   71.72/107.48 = 42.86/x
3. Step 3: Cross multiply
   71.72x = 107.48 × 42.86
4. Step 4: Simplify right side
   71.72x = 4,605.84
5. Step 5: Solve for x
   x = 4,605.84/71.72
6. Step 6: Final answer
   x = 64.22