Finding the Third Proportional to 309,672 and 478,599.75

Step by Step Solution

1. Step 1: Write the proportion equation
   309,672 : 478,599.75 = 478,599.75 : x
2. Step 2: Convert to fraction form
   309,672/478,599.75 = 478,599.75/x
3. Step 3: Cross multiply
   309,672x = 478,599.75 × 478,599.75
4. Step 4: Simplify right side
   309,672x = 229,057,720,700.06
5. Step 5: Solve for x
   x = 229,057,720,700.06/309,672
6. Step 6: Final answer
   x = 739,678.50