Finding the Third Proportional to 397.69 and 871.31

Step by Step Solution

1. Step 1: Write the proportion equation
   397.69 : 871.31 = 871.31 : x
2. Step 2: Convert to fraction form
   397.69/871.31 = 871.31/x
3. Step 3: Cross multiply
   397.69x = 871.31 × 871.31
4. Step 4: Simplify right side
   397.69x = 759,185.47
5. Step 5: Solve for x
   x = 759,185.47/397.69
6. Step 6: Final answer
   x = 1,909.00