Finding the Third Proportional to 390,987 and 856,818

Step by Step Solution

1. Step 1: Write the proportion equation
   390,987 : 856,818 = 856,818 : x
2. Step 2: Convert to fraction form
   390,987/856,818 = 856,818/x
3. Step 3: Cross multiply
   390,987x = 856,818 × 856,818
4. Step 4: Simplify right side
   390,987x = 734,137,085,124
5. Step 5: Solve for x
   x = 734,137,085,124/390,987
6. Step 6: Final answer
   x = 1,877,650.88