Finding the Third Proportional to 312,909 and 672,991.50

Step by Step Solution

1. Step 1: Write the proportion equation
   312,909 : 672,991.50 = 672,991.50 : x
2. Step 2: Convert to fraction form
   312,909/672,991.50 = 672,991.50/x
3. Step 3: Cross multiply
   312,909x = 672,991.50 × 672,991.50
4. Step 4: Simplify right side
   312,909x = 452,917,559,072.25
5. Step 5: Solve for x
   x = 452,917,559,072.25/312,909
6. Step 6: Final answer
   x = 1,447,441.78