Finding the Third Proportional to 358,456.50 and 782,128

Step by Step Solution

1. Step 1: Write the proportion equation
   358,456.50 : 782,128 = 782,128 : x
2. Step 2: Convert to fraction form
   358,456.50/782,128 = 782,128/x
3. Step 3: Cross multiply
   358,456.50x = 782,128 × 782,128
4. Step 4: Simplify right side
   358,456.50x = 611,724,208,384
5. Step 5: Solve for x
   x = 611,724,208,384/358,456.50
6. Step 6: Final answer
   x = 1,706,550.75