Finding the Third Proportional to 309,108 and 645,000

Step by Step Solution

1. Step 1: Write the proportion equation
   309,108 : 645,000 = 645,000 : x
2. Step 2: Convert to fraction form
   309,108/645,000 = 645,000/x
3. Step 3: Cross multiply
   309,108x = 645,000 × 645,000
4. Step 4: Simplify right side
   309,108x = 416,025,000,000
5. Step 5: Solve for x
   x = 416,025,000,000/309,108
6. Step 6: Final answer
   x = 1,345,888.82