Finding the Third Proportional to 390,112 and 851,665

Step by Step Solution

1. Step 1: Write the proportion equation
   390,112 : 851,665 = 851,665 : x
2. Step 2: Convert to fraction form
   390,112/851,665 = 851,665/x
3. Step 3: Cross multiply
   390,112x = 851,665 × 851,665
4. Step 4: Simplify right side
   390,112x = 725,333,272,225
5. Step 5: Solve for x
   x = 725,333,272,225/390,112
6. Step 6: Final answer
   x = 1,859,294.95