Finding the Third Proportional to 3,987,816 and 8,648,688

Step by Step Solution

1. Step 1: Write the proportion equation
   3,987,816 : 8,648,688 = 8,648,688 : x
2. Step 2: Convert to fraction form
   3,987,816/8,648,688 = 8,648,688/x
3. Step 3: Cross multiply
   3,987,816x = 8,648,688 × 8,648,688
4. Step 4: Simplify right side
   3,987,816x = 74,799,804,121,344
5. Step 5: Solve for x
   x = 74,799,804,121,344/3,987,816
6. Step 6: Final answer
   x = 18,757,085.11