Finding the Third Proportional to 291,831 and 639,022.50

Step by Step Solution

1. Step 1: Write the proportion equation
   291,831 : 639,022.50 = 639,022.50 : x
2. Step 2: Convert to fraction form
   291,831/639,022.50 = 639,022.50/x
3. Step 3: Cross multiply
   291,831x = 639,022.50 × 639,022.50
4. Step 4: Simplify right side
   291,831x = 408,349,755,506.25
5. Step 5: Solve for x
   x = 408,349,755,506.25/291,831
6. Step 6: Final answer
   x = 1,399,267.92