Finding the Third Proportional to 311,959.50 and 638,706

Step by Step Solution

1. Step 1: Write the proportion equation
   311,959.50 : 638,706 = 638,706 : x
2. Step 2: Convert to fraction form
   311,959.50/638,706 = 638,706/x
3. Step 3: Cross multiply
   311,959.50x = 638,706 × 638,706
4. Step 4: Simplify right side
   311,959.50x = 407,945,354,436
5. Step 5: Solve for x
   x = 407,945,354,436/311,959.50
6. Step 6: Final answer
   x = 1,307,686.91