Finding the Third Proportional to 390,200 and 851,308

Step by Step Solution

1. Step 1: Write the proportion equation
   390,200 : 851,308 = 851,308 : x
2. Step 2: Convert to fraction form
   390,200/851,308 = 851,308/x
3. Step 3: Cross multiply
   390,200x = 851,308 × 851,308
4. Step 4: Simplify right side
   390,200x = 724,725,310,864
5. Step 5: Solve for x
   x = 724,725,310,864/390,200
6. Step 6: Final answer
   x = 1,857,317.56