Finding the Third Proportional to 243,151.50 and 390,678

Step by Step Solution

1. Step 1: Write the proportion equation
   243,151.50 : 390,678 = 390,678 : x
2. Step 2: Convert to fraction form
   243,151.50/390,678 = 390,678/x
3. Step 3: Cross multiply
   243,151.50x = 390,678 × 390,678
4. Step 4: Simplify right side
   243,151.50x = 152,629,299,684
5. Step 5: Solve for x
   x = 152,629,299,684/243,151.50
6. Step 6: Final answer
   x = 627,712.76