Finding the Third Proportional to 311,986.50 and 638,754

Step by Step Solution

1. Step 1: Write the proportion equation
   311,986.50 : 638,754 = 638,754 : x
2. Step 2: Convert to fraction form
   311,986.50/638,754 = 638,754/x
3. Step 3: Cross multiply
   311,986.50x = 638,754 × 638,754
4. Step 4: Simplify right side
   311,986.50x = 408,006,672,516
5. Step 5: Solve for x
   x = 408,006,672,516/311,986.50
6. Step 6: Final answer
   x = 1,307,770.28