Finding the Third Proportional to 243,309 and 387,445.50

Step by Step Solution

1. Step 1: Write the proportion equation
   243,309 : 387,445.50 = 387,445.50 : x
2. Step 2: Convert to fraction form
   243,309/387,445.50 = 387,445.50/x
3. Step 3: Cross multiply
   243,309x = 387,445.50 × 387,445.50
4. Step 4: Simplify right side
   243,309x = 150,114,015,470.25
5. Step 5: Solve for x
   x = 150,114,015,470.25/243,309
6. Step 6: Final answer
   x = 616,968.61