Finding the Third Proportional to 99,904.50 and 213,979.50

Step by Step Solution

1. Step 1: Write the proportion equation
   99,904.50 : 213,979.50 = 213,979.50 : x
2. Step 2: Convert to fraction form
   99,904.50/213,979.50 = 213,979.50/x
3. Step 3: Cross multiply
   99,904.50x = 213,979.50 × 213,979.50
4. Step 4: Simplify right side
   99,904.50x = 45,787,226,420.25
5. Step 5: Solve for x
   x = 45,787,226,420.25/99,904.50
6. Step 6: Final answer
   x = 458,309.95