Finding the Third Proportional to 681.56 and 1,057.31

Step by Step Solution

1. Step 1: Write the proportion equation
   681.56 : 1,057.31 = 1,057.31 : x
2. Step 2: Convert to fraction form
   681.56/1,057.31 = 1,057.31/x
3. Step 3: Cross multiply
   681.56x = 1,057.31 × 1,057.31
4. Step 4: Simplify right side
   681.56x = 1,117,909.72
5. Step 5: Solve for x
   x = 1,117,909.72/681.56
6. Step 6: Final answer
   x = 1,640.22