Finding the Third Proportional to 390,847 and 856,510

Step by Step Solution

1. Step 1: Write the proportion equation
   390,847 : 856,510 = 856,510 : x
2. Step 2: Convert to fraction form
   390,847/856,510 = 856,510/x
3. Step 3: Cross multiply
   390,847x = 856,510 × 856,510
4. Step 4: Simplify right side
   390,847x = 733,609,380,100
5. Step 5: Solve for x
   x = 733,609,380,100/390,847
6. Step 6: Final answer
   x = 1,876,973.29