Finding the Third Proportional to 309,721.50 and 454,345.50

Step by Step Solution

1. Step 1: Write the proportion equation
   309,721.50 : 454,345.50 = 454,345.50 : x
2. Step 2: Convert to fraction form
   309,721.50/454,345.50 = 454,345.50/x
3. Step 3: Cross multiply
   309,721.50x = 454,345.50 × 454,345.50
4. Step 4: Simplify right side
   309,721.50x = 206,429,833,370.25
5. Step 5: Solve for x
   x = 206,429,833,370.25/309,721.50
6. Step 6: Final answer
   x = 666,501.46