Finding the Third Proportional to 311,931 and 638,616.75

Step by Step Solution

1. Step 1: Write the proportion equation
   311,931 : 638,616.75 = 638,616.75 : x
2. Step 2: Convert to fraction form
   311,931/638,616.75 = 638,616.75/x
3. Step 3: Cross multiply
   311,931x = 638,616.75 × 638,616.75
4. Step 4: Simplify right side
   311,931x = 407,831,353,380.56
5. Step 5: Solve for x
   x = 407,831,353,380.56/311,931
6. Step 6: Final answer
   x = 1,307,440.92