Finding the Third Proportional to 309,353.50 and 678,485

Step by Step Solution

1. Step 1: Write the proportion equation
   309,353.50 : 678,485 = 678,485 : x
2. Step 2: Convert to fraction form
   309,353.50/678,485 = 678,485/x
3. Step 3: Cross multiply
   309,353.50x = 678,485 × 678,485
4. Step 4: Simplify right side
   309,353.50x = 460,341,895,225
5. Step 5: Solve for x
   x = 460,341,895,225/309,353.50
6. Step 6: Final answer
   x = 1,488,077.22