Finding the Third Proportional to 300,636 and 640,260

Step by Step Solution

1. Step 1: Write the proportion equation
   300,636 : 640,260 = 640,260 : x
2. Step 2: Convert to fraction form
   300,636/640,260 = 640,260/x
3. Step 3: Cross multiply
   300,636x = 640,260 × 640,260
4. Step 4: Simplify right side
   300,636x = 409,932,867,600
5. Step 5: Solve for x
   x = 409,932,867,600/300,636
6. Step 6: Final answer
   x = 1,363,552.16