Finding the Third Proportional to 3,920.06 and 8,440.31

Step by Step Solution

1. Step 1: Write the proportion equation
   3,920.06 : 8,440.31 = 8,440.31 : x
2. Step 2: Convert to fraction form
   3,920.06/8,440.31 = 8,440.31/x
3. Step 3: Cross multiply
   3,920.06x = 8,440.31 × 8,440.31
4. Step 4: Simplify right side
   3,920.06x = 71,238,875.10
5. Step 5: Solve for x
   x = 71,238,875.10/3,920.06
6. Step 6: Final answer
   x = 18,172.89