Finding the Third Proportional to 99,909 and 209,055

Step by Step Solution

1. Step 1: Write the proportion equation
   99,909 : 209,055 = 209,055 : x
2. Step 2: Convert to fraction form
   99,909/209,055 = 209,055/x
3. Step 3: Cross multiply
   99,909x = 209,055 × 209,055
4. Step 4: Simplify right side
   99,909x = 43,703,993,025
5. Step 5: Solve for x
   x = 43,703,993,025/99,909
6. Step 6: Final answer
   x = 437,438.00