Finding the Third Proportional to 390,998 and 851,980

Step by Step Solution

1. Step 1: Write the proportion equation
   390,998 : 851,980 = 851,980 : x
2. Step 2: Convert to fraction form
   390,998/851,980 = 851,980/x
3. Step 3: Cross multiply
   390,998x = 851,980 × 851,980
4. Step 4: Simplify right side
   390,998x = 725,869,920,400
5. Step 5: Solve for x
   x = 725,869,920,400/390,998
6. Step 6: Final answer
   x = 1,856,454.31