Finding the Third Proportional to 311,398 and 680,960

Step by Step Solution

1. Step 1: Write the proportion equation
   311,398 : 680,960 = 680,960 : x
2. Step 2: Convert to fraction form
   311,398/680,960 = 680,960/x
3. Step 3: Cross multiply
   311,398x = 680,960 × 680,960
4. Step 4: Simplify right side
   311,398x = 463,706,521,600
5. Step 5: Solve for x
   x = 463,706,521,600/311,398
6. Step 6: Final answer
   x = 1,489,112.07