Finding the Third Proportional to 10,420 and 13,920

Step by Step Solution

1. Step 1: Write the proportion equation
   10,420 : 13,920 = 13,920 : x
2. Step 2: Convert to fraction form
   10,420/13,920 = 13,920/x
3. Step 3: Cross multiply
   10,420x = 13,920 × 13,920
4. Step 4: Simplify right side
   10,420x = 193,766,400
5. Step 5: Solve for x
   x = 193,766,400/10,420
6. Step 6: Final answer
   x = 18,595.62