Finding the Third Proportional to 309,906.50 and 478,528.50

Step by Step Solution

1. Step 1: Write the proportion equation
   309,906.50 : 478,528.50 = 478,528.50 : x
2. Step 2: Convert to fraction form
   309,906.50/478,528.50 = 478,528.50/x
3. Step 3: Cross multiply
   309,906.50x = 478,528.50 × 478,528.50
4. Step 4: Simplify right side
   309,906.50x = 228,989,525,312.25
5. Step 5: Solve for x
   x = 228,989,525,312.25/309,906.50
6. Step 6: Final answer
   x = 738,898.75