Finding the Third Proportional to 309,021 and 478,428.50

Step by Step Solution

1. Step 1: Write the proportion equation
   309,021 : 478,428.50 = 478,428.50 : x
2. Step 2: Convert to fraction form
   309,021/478,428.50 = 478,428.50/x
3. Step 3: Cross multiply
   309,021x = 478,428.50 × 478,428.50
4. Step 4: Simplify right side
   309,021x = 228,893,829,612.25
5. Step 5: Solve for x
   x = 228,893,829,612.25/309,021
6. Step 6: Final answer
   x = 740,706.39