Finding the Third Proportional to 640,272 and 1,389,072

Step by Step Solution

1. Step 1: Write the proportion equation
   640,272 : 1,389,072 = 1,389,072 : x
2. Step 2: Convert to fraction form
   640,272/1,389,072 = 1,389,072/x
3. Step 3: Cross multiply
   640,272x = 1,389,072 × 1,389,072
4. Step 4: Simplify right side
   640,272x = 1,929,521,021,184
5. Step 5: Solve for x
   x = 1,929,521,021,184/640,272
6. Step 6: Final answer
   x = 3,013,595.82