Finding the Third Proportional to 309,258 and 435,495

Step by Step Solution

1. Step 1: Write the proportion equation
   309,258 : 435,495 = 435,495 : x
2. Step 2: Convert to fraction form
   309,258/435,495 = 435,495/x
3. Step 3: Cross multiply
   309,258x = 435,495 × 435,495
4. Step 4: Simplify right side
   309,258x = 189,655,895,025
5. Step 5: Solve for x
   x = 189,655,895,025/309,258
6. Step 6: Final answer
   x = 613,261.08