Finding the Third Proportional to 309,410 and 478,686

Step by Step Solution

1. Step 1: Write the proportion equation
   309,410 : 478,686 = 478,686 : x
2. Step 2: Convert to fraction form
   309,410/478,686 = 478,686/x
3. Step 3: Cross multiply
   309,410x = 478,686 × 478,686
4. Step 4: Simplify right side
   309,410x = 229,140,286,596
5. Step 5: Solve for x
   x = 229,140,286,596/309,410
6. Step 6: Final answer
   x = 740,571.69