Finding the Third Proportional to 99,909 and 213,988.50

Step by Step Solution

1. Step 1: Write the proportion equation
   99,909 : 213,988.50 = 213,988.50 : x
2. Step 2: Convert to fraction form
   99,909/213,988.50 = 213,988.50/x
3. Step 3: Cross multiply
   99,909x = 213,988.50 × 213,988.50
4. Step 4: Simplify right side
   99,909x = 45,791,078,132.25
5. Step 5: Solve for x
   x = 45,791,078,132.25/99,909
6. Step 6: Final answer
   x = 458,327.86