Finding the Third Proportional to 292,342.50 and 639,360

Step by Step Solution

1. Step 1: Write the proportion equation
   292,342.50 : 639,360 = 639,360 : x
2. Step 2: Convert to fraction form
   292,342.50/639,360 = 639,360/x
3. Step 3: Cross multiply
   292,342.50x = 639,360 × 639,360
4. Step 4: Simplify right side
   292,342.50x = 408,781,209,600
5. Step 5: Solve for x
   x = 408,781,209,600/292,342.50
6. Step 6: Final answer
   x = 1,398,295.53