Finding the Third Proportional to 390,109.50 and 851,661

Step by Step Solution

1. Step 1: Write the proportion equation
   390,109.50 : 851,661 = 851,661 : x
2. Step 2: Convert to fraction form
   390,109.50/851,661 = 851,661/x
3. Step 3: Cross multiply
   390,109.50x = 851,661 × 851,661
4. Step 4: Simplify right side
   390,109.50x = 725,326,458,921
5. Step 5: Solve for x
   x = 725,326,458,921/390,109.50
6. Step 6: Final answer
   x = 1,859,289.40