Finding the Third Proportional to 20,139 and 42,678

Step by Step Solution

1. Step 1: Write the proportion equation
   20,139 : 42,678 = 42,678 : x
2. Step 2: Convert to fraction form
   20,139/42,678 = 42,678/x
3. Step 3: Cross multiply
   20,139x = 42,678 × 42,678
4. Step 4: Simplify right side
   20,139x = 1,821,411,684
5. Step 5: Solve for x
   x = 1,821,411,684/20,139
6. Step 6: Final answer
   x = 90,442.01