Finding the Third Proportional to 639,264 and 1,389,120

Step by Step Solution

1. Step 1: Write the proportion equation
   639,264 : 1,389,120 = 1,389,120 : x
2. Step 2: Convert to fraction form
   639,264/1,389,120 = 1,389,120/x
3. Step 3: Cross multiply
   639,264x = 1,389,120 × 1,389,120
4. Step 4: Simplify right side
   639,264x = 1,929,654,374,400
5. Step 5: Solve for x
   x = 1,929,654,374,400/639,264
6. Step 6: Final answer
   x = 3,018,556.30