Finding the Third Proportional to 390,609 and 856,008

Step by Step Solution

1. Step 1: Write the proportion equation
   390,609 : 856,008 = 856,008 : x
2. Step 2: Convert to fraction form
   390,609/856,008 = 856,008/x
3. Step 3: Cross multiply
   390,609x = 856,008 × 856,008
4. Step 4: Simplify right side
   390,609x = 732,749,696,064
5. Step 5: Solve for x
   x = 732,749,696,064/390,609
6. Step 6: Final answer
   x = 1,875,916.06