Finding the Fourth Proportional to 71.86, 107.86 and 31.31

Step by Step Solution

1. Step 1: Write the proportion equation
   71.86 : 107.86 = 31.31 : x
2. Step 2: Convert to fraction form
   71.86/107.86 = 31.31/x
3. Step 3: Cross multiply
   71.86x = 107.86 × 31.31
4. Step 4: Simplify right side
   71.86x = 3,376.48
5. Step 5: Solve for x
   x = 3,376.48/71.86
6. Step 6: Final answer
   x = 46.99