Finding the Third Proportional to 200,978 and 418,495

Step by Step Solution

1. Step 1: Write the proportion equation
   200,978 : 418,495 = 418,495 : x
2. Step 2: Convert to fraction form
   200,978/418,495 = 418,495/x
3. Step 3: Cross multiply
   200,978x = 418,495 × 418,495
4. Step 4: Simplify right side
   200,978x = 175,138,065,025
5. Step 5: Solve for x
   x = 175,138,065,025/200,978
6. Step 6: Final answer
   x = 871,429.04