Finding the Third Proportional to 20,388 and 42,720

Step by Step Solution

1. Step 1: Write the proportion equation
   20,388 : 42,720 = 42,720 : x
2. Step 2: Convert to fraction form
   20,388/42,720 = 42,720/x
3. Step 3: Cross multiply
   20,388x = 42,720 × 42,720
4. Step 4: Simplify right side
   20,388x = 1,824,998,400
5. Step 5: Solve for x
   x = 1,824,998,400/20,388
6. Step 6: Final answer
   x = 89,513.36