Finding the Third Proportional to 5,538,909 and 8,128,644

Step by Step Solution

1. Step 1: Write the proportion equation
   5,538,909 : 8,128,644 = 8,128,644 : x
2. Step 2: Convert to fraction form
   5,538,909/8,128,644 = 8,128,644/x
3. Step 3: Cross multiply
   5,538,909x = 8,128,644 × 8,128,644
4. Step 4: Simplify right side
   5,538,909x = 66,074,853,278,736
5. Step 5: Solve for x
   x = 66,074,853,278,736/5,538,909
6. Step 6: Final answer
   x = 11,929,218.06