Finding the Third Proportional to 3,920 and 8,404

Step by Step Solution

1. Step 1: Write the proportion equation
   3,920 : 8,404 = 8,404 : x
2. Step 2: Convert to fraction form
   3,920/8,404 = 8,404/x
3. Step 3: Cross multiply
   3,920x = 8,404 × 8,404
4. Step 4: Simplify right side
   3,920x = 70,627,216
5. Step 5: Solve for x
   x = 70,627,216/3,920
6. Step 6: Final answer
   x = 18,017.15