Finding the Third Proportional to 21,681,978 and 42,815,604

Step by Step Solution

1. Step 1: Write the proportion equation
   21,681,978 : 42,815,604 = 42,815,604 : x
2. Step 2: Convert to fraction form
   21,681,978/42,815,604 = 42,815,604/x
3. Step 3: Cross multiply
   21,681,978x = 42,815,604 × 42,815,604
4. Step 4: Simplify right side
   21,681,978x = 1,833,175,945,884,816
5. Step 5: Solve for x
   x = 1,833,175,945,884,816/21,681,978
6. Step 6: Final answer
   x = 84,548,372.20