Finding the Third Proportional to 3,879,320 and 8,430,128

Step by Step Solution

1. Step 1: Write the proportion equation
   3,879,320 : 8,430,128 = 8,430,128 : x
2. Step 2: Convert to fraction form
   3,879,320/8,430,128 = 8,430,128/x
3. Step 3: Cross multiply
   3,879,320x = 8,430,128 × 8,430,128
4. Step 4: Simplify right side
   3,879,320x = 71,067,058,096,384
5. Step 5: Solve for x
   x = 71,067,058,096,384/3,879,320
6. Step 6: Final answer
   x = 18,319,462.71