Finding the Third Proportional to 309,920 and 436,428

Step by Step Solution

1. Step 1: Write the proportion equation
   309,920 : 436,428 = 436,428 : x
2. Step 2: Convert to fraction form
   309,920/436,428 = 436,428/x
3. Step 3: Cross multiply
   309,920x = 436,428 × 436,428
4. Step 4: Simplify right side
   309,920x = 190,469,399,184
5. Step 5: Solve for x
   x = 190,469,399,184/309,920
6. Step 6: Final answer
   x = 614,576.02