Finding the Third Proportional to 311,956.50 and 638,664

Step by Step Solution

1. Step 1: Write the proportion equation
   311,956.50 : 638,664 = 638,664 : x
2. Step 2: Convert to fraction form
   311,956.50/638,664 = 638,664/x
3. Step 3: Cross multiply
   311,956.50x = 638,664 × 638,664
4. Step 4: Simplify right side
   311,956.50x = 407,891,704,896
5. Step 5: Solve for x
   x = 407,891,704,896/311,956.50
6. Step 6: Final answer
   x = 1,307,527.51