Finding the Third Proportional to 399,366 and 859,621.50

Step by Step Solution

1. Step 1: Write the proportion equation
   399,366 : 859,621.50 = 859,621.50 : x
2. Step 2: Convert to fraction form
   399,366/859,621.50 = 859,621.50/x
3. Step 3: Cross multiply
   399,366x = 859,621.50 × 859,621.50
4. Step 4: Simplify right side
   399,366x = 738,949,123,262.25
5. Step 5: Solve for x
   x = 738,949,123,262.25/399,366
6. Step 6: Final answer
   x = 1,850,305.54