Finding the Third Proportional to 392,899.50 and 642,249

Step by Step Solution

1. Step 1: Write the proportion equation
   392,899.50 : 642,249 = 642,249 : x
2. Step 2: Convert to fraction form
   392,899.50/642,249 = 642,249/x
3. Step 3: Cross multiply
   392,899.50x = 642,249 × 642,249
4. Step 4: Simplify right side
   392,899.50x = 412,483,778,001
5. Step 5: Solve for x
   x = 412,483,778,001/392,899.50
6. Step 6: Final answer
   x = 1,049,845.52