Finding the Third Proportional to 20,840 and 42,456

Step by Step Solution

1. Step 1: Write the proportion equation
   20,840 : 42,456 = 42,456 : x
2. Step 2: Convert to fraction form
   20,840/42,456 = 42,456/x
3. Step 3: Cross multiply
   20,840x = 42,456 × 42,456
4. Step 4: Simplify right side
   20,840x = 1,802,511,936
5. Step 5: Solve for x
   x = 1,802,511,936/20,840
6. Step 6: Final answer
   x = 86,492.90