Finding the Third Proportional to 309,408 and 659,280

Step by Step Solution

1. Step 1: Write the proportion equation
   309,408 : 659,280 = 659,280 : x
2. Step 2: Convert to fraction form
   309,408/659,280 = 659,280/x
3. Step 3: Cross multiply
   309,408x = 659,280 × 659,280
4. Step 4: Simplify right side
   309,408x = 434,650,118,400
5. Step 5: Solve for x
   x = 434,650,118,400/309,408
6. Step 6: Final answer
   x = 1,404,779.83