Finding the Third Proportional to 90,456 and 209,580

Step by Step Solution

1. Step 1: Write the proportion equation
   90,456 : 209,580 = 209,580 : x
2. Step 2: Convert to fraction form
   90,456/209,580 = 209,580/x
3. Step 3: Cross multiply
   90,456x = 209,580 × 209,580
4. Step 4: Simplify right side
   90,456x = 43,923,776,400
5. Step 5: Solve for x
   x = 43,923,776,400/90,456
6. Step 6: Final answer
   x = 485,581.68