Finding the Third Proportional to 311,943 and 638,636.25

Step by Step Solution

1. Step 1: Write the proportion equation
   311,943 : 638,636.25 = 638,636.25 : x
2. Step 2: Convert to fraction form
   311,943/638,636.25 = 638,636.25/x
3. Step 3: Cross multiply
   311,943x = 638,636.25 × 638,636.25
4. Step 4: Simplify right side
   311,943x = 407,856,259,814.06
5. Step 5: Solve for x
   x = 407,856,259,814.06/311,943
6. Step 6: Final answer
   x = 1,307,470.47